| 1. |
- Bakx, Tom, 1990, et al.
(författare)
-
A dusty protocluster surrounding the binary galaxy HerBS-70 at z = 2.3
- 2024
-
Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 530:4, s. 4578-4596
-
Tidskriftsartikel (refereegranskat)abstract
- We report on deep SCUBA-2 observations at 850 μm and NOrthern Extended Millimetre Array (NOEMA) spectroscopic measurements at 2 mm of the environment surrounding the luminous, massive (M∗ ≈ 2 × 1011 M☉) Herschel-selected source HerBS-70. This source was revealed by previous NOEMA observations to be a binary system of dusty star-forming galaxies at z = 2.3, with the east component (HerBS-70E) hosting an active galactic nucleus. The SCUBA-2 observations detected, in addition to the binary system, 21 sources at >3.5σ over an area of ∼25 square comoving Mpc with a sensitivity of 1σ850 = 0.75 mJy. The surface density of continuum sources around HerBS-70 is three times higher than for field galaxies. The NOEMA spectroscopic measurements confirm the protocluster membership of three of the nine brightest sources through their CO(4–3) line emission, yielding a volume density 36 times higher than for field galaxies. All five confirmed sub-mm galaxies in the HerBS-70 system have relatively short gas depletion times (80−500 Myr), indicating the onset of quenching for this protocluster core due to the depletion of gas. The dark matter halo mass of the HerBS-70 system is estimated around 5 × 1013 M☉, with a projected current-day mass of 1015 M☉, similar to the local Virgo and Coma clusters. These observations support the claim that DSFGs, in particular the ones with observed multiplicity, can trace cosmic overdensities.
|
|
| 2. |
- Bendo, G. J., et al.
(författare)
-
The bright extragalactic ALMA redshift survey (BEARS) – II. Millimetre photometry of gravitational lens candidates
- 2023
-
Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 522:2, s. 2995-3017
-
Tidskriftsartikel (refereegranskat)abstract
- We present 101- and 151-GHz ALMA continuum images for 85 fields selected from Herschel observations that have 500-μm flux densities >80 mJy and 250–500-μm colours consistent with z > 2, most of which are expected to be gravitationally lensed or hyperluminous infrared galaxies. Approximately half of the Herschel 500-μm sources were resolved into multiple ALMA sources, but 11 of the 15 brightest 500-μm Herschel sources correspond to individual ALMA sources. For the 37 fields containing either a single source with a spectroscopic redshift or two sources with the same spectroscopic redshift, we examined the colour temperatures and dust emissivity indices. The colour temperatures only vary weakly with redshift and are statistically consistent with no redshift-dependent temperature variations, which generally corresponds to results from other samples selected in far-infrared, submillimetre, or millimetre bands but not to results from samples selected in optical or near-infrared bands. The dust emissivity indices, with very few exceptions, are largely consistent with a value of 2. We also compared spectroscopic redshifts to photometric redshifts based on spectral energy distribution templates designed for infrared-bright high-redshift galaxies. While the templates systematically underestimate the redshifts by ∼15 per cent, the inclusion of ALMA data decreases the scatter in the predicted redshifts by a factor of ∼2, illustrating the potential usefulness of these millimetre data for estimating photometric redshifts.
|
|
| 3. |
- Berta, S., et al.
(författare)
-
z -GAL: A NOEMA spectroscopic redshift survey of bright Herschel galaxies: III. Physical properties
- 2023
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 678
-
Tidskriftsartikel (refereegranskat)abstract
- The z-GAL survey observed 137 bright Herschel-selected targets with the IRAM Northern Extended Millimeter Array, with the aim to measure their redshift and study their properties. Several of them have been resolved into multiple sources. Consequently, robust spectroscopic redshifts have been measured for 165 individual galaxies in the range 0.8., <., z., <., 6.5. In this paper we analyse the millimetre spectra of the z-GAL sources, using both their continuum and line emission to derive their physical properties. At least two spectral lines are detected for each source, including transitions of 12CO, [CI], and H2O. The observed 12CO line ratios and spectral line energy distributions of individual sources resemble those of local starbursts. In seven sources the para-H2O (211-202) transition is detected and follows the IR versus H2O luminosity relation of sub-millimetre galaxies. The molecular gas mass of the z-GAL sources is derived from their 12CO, [CI], and sub-millimetre dust continuum emission. The three tracers lead to consistent results, with the dust continuum showing the largest scatter when compared to 12CO. The gas-to-dust mass ratio of these sources was computed by combining the information derived from 12CO and the dust continuum and has a median value of 107, similar to star-forming galaxies of near-solar metallicity. The same combined analysis leads to depletion timescales in the range between 0.1 and 1.0 Gyr, which place the z-GAL sources between the main sequence' of star formation and the locus of starbursts. Finally, we derived a first estimate of stellar masses "modulo possible gravitational magnification "by inverting known gas scaling relations: the z-GAL sample is confirmed to be mostly composed by starbursts, whereas ∼25% of its members lie on the main sequence of star-forming galaxies (within ±0.5 dex).
|
|
| 4. |
- Boone, F., et al.
(författare)
-
An extended Herschel drop-out source in the center of AS1063: A normal dusty galaxy at z = 6.1 or SZ substructures?
- 2013
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 559, s. L1-
-
Tidskriftsartikel (refereegranskat)abstract
- In the course of our 870 μm APEX/LABOCA follow-up of the Herschel Lensing Survey we have detected a source in AS1063 (RXC J2248.7-4431) that has no counterparts in any of the Herschel PACS/SPIRE bands, it is a Herschel "drop-out" with S870=S500 ≥ 0:5. The 870 μm emission is extended and centered on the brightest cluster galaxy, suggesting either a multiply imaged background source or substructure in the Sunyaev-Zel'dovich increment due to inhomogeneities in the hot cluster gas of this merging cluster. We discuss both interpretations with emphasis on the putative lensed source. Based on the observed properties and on our lens model we find that this source may be the first submillimeter galaxy (SMG) with a moderate far-infrared (FIR) luminosity (LFIR. © ESO 2013.
|
|
| 5. |
- Canameras, R., et al.
(författare)
-
Plancks dusty gems: VI. Multi-j co excitation and interstellar medium conditions in dusty starburst galaxies at z = 2 - 4*
- 2018
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 620
-
Tidskriftsartikel (refereegranskat)abstract
- We present an extensive CO emission-line survey of the Planck's dusty Gravitationally Enhanced subMillimetre Sources, a small set of 11 strongly lensed dusty star-forming galaxies at z = 2-4 discovered with Planck and Herschel satellites, using EMIR on the IRAM 30-m telescope. We detected a total of 45 CO rotational lines from Jup= 3 to Jup= 11, and up to eight transitions per source, allowing a detailed analysis of the gas excitation and interstellar medium conditions within these extremely bright (μLFIR= 0.5 - 3.0 × 1014L⊙), vigorous starbursts. The peak of the CO spectral-line energy distributions (SLEDs) fall between Jup= 4 and Jup= 7 for nine out of 11 sources, in the same range as other lensed and unlensed submillimeter galaxies (SMGs) and the inner regions of local starbursts. We applied radiative transfer models using the large velocity gradient approach to infer the spatially-averaged molecular gas densities, nH2≃102.6- 104.1cm-3, and kinetic temperatures, Tk≃30-1000 K. In five sources, we find evidence of two distinct gas phases with different properties and model their CO SLED with two excitation components. The warm (70-320 K) and dense gas reservoirs in these galaxies are highly excited, while the cooler (15-60 K) and more extended low-excitation components cover a range of gas densities. In two sources, the latter is associated with diffuse Milky Way-like gas phases of density nH2≃102.4- 102.8cm-3, which provides evidence that a significant fraction of the total gas masses of dusty starburst galaxies can be embedded in cool, low-density reservoirs. The delensed masses of the warm star-forming molecular gas range from 0.6to12 × 1010M⊙. Finally, we show that the CO line luminosity ratios are consistent with those predicted by models of photon-dominated regions (PDRs) and disfavor scenarios of gas clouds irradiated by intense X-ray fields from active galactic nuclei. By combining CO, [C I] and [C II] line diagnostics, we obtain average PDR gas densities significantly higher than in normal star-forming galaxies at low-redshift, as well as far-ultraviolet radiation fields 102-104times more intense than in the Milky Way. These spatially-averaged conditions are consistent with those in high-redshift SMGs and in a range of low-redshift environments, from the central regions of ultra-luminous infrared galaxies and bluer starbursts to Galactic giant molecular clouds.
|
|
| 6. |
- Chown, Ryan, et al.
(författare)
-
PDRs4All: IV. An embarrassment of riches: Aromatic infrared bands in the Orion Bar
- 2024
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 685
-
Tidskriftsartikel (refereegranskat)abstract
- Context. Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs are found at 3.3, 6.2, 7.7, 8.6, and 11.2 µm. The most sensitive, highest-resolution infrared spectral imaging data ever taken of the prototypical PDR, the Orion Bar, have been captured by JWST. These high-quality data allow for an unprecedentedly detailed view of AIBs. Aims. We provide an inventory of the AIBs found in the Orion Bar, along with mid-IR template spectra from five distinct regions in the Bar: the molecular PDR (i.e. the three H2 dissociation fronts), the atomic PDR, and the H II region. Methods. We used JWST NIRSpec IFU and MIRI MRS observations of the Orion Bar from the JWST Early Release Science Program, PDRs4All (ID: 1288). We extracted five template spectra to represent the morphology and environment of the Orion Bar PDR. We investigated and characterised the AIBs in these template spectra. We describe the variations among them here. Results. The superb sensitivity and the spectral and spatial resolution of these JWST observations reveal many details of the AIB emission and enable an improved characterization of their detailed profile shapes and sub-components. The Orion Bar spectra are dominated by the well-known AIBs at 3.3, 6.2, 7.7, 8.6, 11.2, and 12.7 µm with well-defined profiles. In addition, the spectra display a wealth of weaker features and sub-components. The widths of many AIBs show clear and systematic variations, being narrowest in the atomic PDR template, but showing a clear broadening in the H II region template while the broadest bands are found in the three dissociation front templates. In addition, the relative strengths of AIB (sub-)components vary among the template spectra as well. All AIB profiles are characteristic of class A sources as designated by Peeters (2022, A&A, 390, 1089), except for the 11.2 µm AIB profile deep in the molecular zone, which belongs to class B11.2. Furthermore, the observations show that the sub-components that contribute to the 5.75, 7.7, and 11.2 µm AIBs become much weaker in the PDR surface layers. We attribute this to the presence of small, more labile carriers in the deeper PDR layers that are photolysed away in the harsh radiation field near the surface. The 3.3/11.2 AIB intensity ratio decreases by about 40% between the dissociation fronts and the H II region, indicating a shift in the polycyclic aromatic hydrocarbon (PAH) size distribution to larger PAHs in the PDR surface layers, also likely due to the effects of photochemistry. The observed broadening of the bands in the molecular PDR is consistent with an enhanced importance of smaller PAHs since smaller PAHs attain a higher internal excitation energy at a fixed photon energy. Conclusions. Spectral-imaging observations of the Orion Bar using JWST yield key insights into the photochemical evolution of PAHs, such as the evolution responsible for the shift of 11.2 µm AIB emission from class B11.2 in the molecular PDR to class A11.2 in the PDR surface layers. This photochemical evolution is driven by the increased importance of FUV processing in the PDR surface layers, resulting in a “weeding out” of the weakest links of the PAH family in these layers. For now, these JWST observations are consistent with a model in which the underlying PAH family is composed of a few species: the so-called ‘grandPAHs’.
|
|
| 7. |
- Cox, P., et al.
(författare)
-
z-GAL: A NOEMA spectroscopic redshift survey of bright Herschel galaxies: I. Overview
- 2023
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 678
-
Tidskriftsartikel (refereegranskat)abstract
- Using the IRAM NOrthern Extended Millimetre Array (NOEMA), we conducted a Large Programme (z-GAL) to measure redshifts for 126 bright galaxies detected in the Herschel Astrophysical Large Area Survey (H-ATLAS), the HerMES Large Mode Survey (HeLMS), and the Herschel Stripe 82 (HerS) Survey. We report reliable spectroscopic redshifts for a total of 124 of the Herschel-selected galaxies. The redshifts are estimated from scans of the 3 and 2-mm bands (and, for one source, the 1-mm band), covering up to 31 GHz in each band, and are based on the detection of at least two emission lines. Together with the Pilot Programme, where 11 sources had their spectroscopic redshifts measured, our survey has derived precise redshifts for 135 bright Herschel-selected galaxies, making it the largest sample of high-z galaxies with robust redshifts to date. Most emission lines detected are from 12CO (mainly from J = 2 1 to 5 4), with some sources seen in [CI] and H2O emission lines. The spectroscopic redshifts are in the range 0.8
|
|
| 8. |
- Gullberg, B., et al.
(författare)
-
ALMA finds dew drops in the dusty spider's web
- 2016
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 591
-
Tidskriftsartikel (refereegranskat)abstract
- We present 0 ''.5 resolution ALMA detections of the observed 246 GHz continuum, [CI] P-3(2) -> P-3(1) fine structure line ([CI] 2-1), CO(7-6), and H2O lines in the z = 2:161 radio galaxy MRC1138-262, the so-called Spiderweb galaxy. We detect strong [CI] 2-1 emission both at the position of the radio core, and in a second component similar to 4 kpc away from it. The 1100 km s(-1) broad [CI]2-1 line in this latter component, combined with its H-2 mass of 1 : 6 x 10(10) M-circle dot, implies that this emission must come from a compact region
|
|
| 9. |
- Habart, Emilie, et al.
(författare)
-
PDRs4All II. JWST’s NIR and MIR imaging view of the Orion Nebula
- 2024
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 685
-
Tidskriftsartikel (refereegranskat)abstract
- Context. The James Webb Space Telescope (JWST) has captured the most detailed and sharpest infrared (IR) images ever taken of the inner region of the Orion Nebula, the nearest massive star formation region, and a prototypical highly irradiated dense photo-dissociation region (PDR). Aims. We investigate the fundamental interaction of far-ultraviolet (FUV) photons with molecular clouds. The transitions across the ionization front (IF), dissociation front (DF), and the molecular cloud are studied at high-angular resolution. These transitions are relevant to understanding the effects of radiative feedback from massive stars and the dominant physical and chemical processes that lead to the IR emission that JWST will detect in many Galactic and extragalactic environments. Methods. We utilized NIRCam and MIRI to obtain sub-arcsecond images over ∼150′′ and 42′′ in key gas phase lines (e.g., Pa α, Br α, [FeII] 1.64 µm, H2 1–0 S(1) 2.12 µm, 0–0 S(9) 4.69 µm), aromatic and aliphatic infrared bands (aromatic infrared bands at 3.3–3.4 µm, 7.7, and 11.3 µm), dust emission, and scattered light. Their emission are powerful tracers of the IF and DF, FUV radiation field and density distribution. Using NIRSpec observations the fractional contributions of lines, AIBs, and continuum emission to our NIRCam images were estimated. A very good agreement is found for the distribution and intensity of lines and AIBs between the NIRCam and NIRSpec observations. Results. Due to the proximity of the Orion Nebula and the unprecedented angular resolution of JWST, these data reveal that the molecular cloud borders are hyper structured at small angular scales of ∼0.1–1′′ (∼0.0002–0.002 pc or ∼40–400 au at 414 pc). A diverse set of features are observed such as ridges, waves, globules and photoevaporated protoplanetary disks. At the PDR atomic to molecular transition, several bright features are detected that are associated with the highly irradiated surroundings of the dense molecular condensations and embedded young star. Toward the Orion Bar PDR, a highly sculpted interface is detected with sharp edges and density increases near the IF and DF. This was predicted by previous modeling studies, but the fronts were unresolved in most tracers. The spatial distribution of the AIBs reveals that the PDR edge is steep and is followed by an extensive warm atomic layer up to the DF with multiple ridges. A complex, structured, and folded H0/H2 DF surface was traced by the H2 lines. This dataset was used to revisit the commonly adopted 2D PDR structure of the Orion Bar as our observations show that a 3D “terraced” geometry is required to explain the JWST observations. JWST provides us with a complete view of the PDR, all the way from the PDR edge to the substructured dense region, and this allowed us to determine, in detail, where the emission of the atomic and molecular lines, aromatic bands, and dust originate. Conclusions. This study offers an unprecedented dataset to benchmark and transform PDR physico-chemical and dynamical models for the JWST era. A fundamental step forward in our understanding of the interaction of FUV photons with molecular clouds and the role of FUV irradiation along the star formation sequence is provided.
|
|
| 10. |
- Hagimoto, Masato, et al.
(författare)
-
Bright extragalactic ALMA redshift survey (BEARS) III: detailed study of emission lines from 71 Herschel targets
- 2023
-
Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 521:4, s. 5508-5535
-
Tidskriftsartikel (refereegranskat)abstract
- We analyse the molecular and atomic emission lines of 71 bright Herschel-selected galaxies between redshifts 1.4 and 4.6 detected by the Atacama Large Millimeter/submillimeter Array. These lines include a total of 156 CO, [C i], and H2O emission lines. For 46 galaxies, we detect two transitions of CO lines, and for these galaxies we find gas properties similar to those of other dusty star-forming galaxy (DSFG) samples. A comparison to photodissociation models suggests that most of Herschel-selected galaxies have similar interstellar medium conditions as local infrared-luminous galaxies and high-redshift DSFGs, although with denser gas and more intense far-ultraviolet radiation fields than normal star-forming galaxies. The line luminosities agree with the luminosity scaling relations across five orders of magnitude, although the star formation and gas surface density distributions (i.e. Schmidt-Kennicutt relation) suggest a different star formation phase in our galaxies (and other DSFGs) compared to local and low-redshift gas-rich, normal star-forming systems. The gas-to-dust ratios of these galaxies are similar to Milky Way values, with no apparent redshift evolution. Four of 46 sources appear to have CO line ratios in excess of the expected maximum (thermalized) profile, suggesting a rare phase in the evolution of DSFGs. Finally, we create a deep stacked spectrum over a wide rest-frame frequency (220-890 GHz) that reveals faint transitions from HCN and CH, in line with previous stacking experiments.
|
|
| 11. |
- Ismail, D., et al.
(författare)
-
z-GAL: A NOEMA spectroscopic redshift survey of bright Herschel galaxies: II. Dust properties
- 2023
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 678
-
Tidskriftsartikel (refereegranskat)abstract
- We present the dust properties of 125 bright Herschel galaxies selected from the z-GAL NOEMA spectroscopic redshift survey. All the galaxies have precise spectroscopic redshifts in the range 1.3 < z < 5.4. The large instantaneous bandwidth of NOEMA provides an exquisite sampling of the underlying dust continuum emission at 2 and 3 mm in the observed frame, with flux densities in at least four sidebands for each source. Together with the available Herschel 250, 350, and 500 μm and SCUBA-2 850 μm flux densities, the spectral energy distribution (SED) of each source can be analyzed from the far-infrared to the millimeter, with a fine sampling of the Rayleigh-Jeans tail. This wealth of data provides a solid basis to derive robust dust properties, in particular the dust emissivity index (β) and the dust temperature (Tdust). In order to demonstrate our ability to constrain the dust properties, we used a flux-generated mock catalog and analyzed the results under the assumption of an optically thin and optically thick modified black body emission. The robustness of the SED sampling for the z-GAL sources is highlighted by the mock analysis that showed high accuracy in estimating the continuum dust properties. These findings provided the basis for our detailed analysis of the z-GAL continuum data. We report a range of dust emissivities with β ∼1.5 -3 estimated up to high precision with relative uncertainties that vary in the range 7% 15%, and an average of 2.2 ± 0.3. We find dust temperatures varying from 20 to 50 K with an average of Tdust., ∼30 K for the optically thin case and Tdust., ∼38 K in the optically thick case. For all the sources, we estimate the dust masses and apparent infrared luminosities (based on the optically thin approach). An inverse correlation is found between Tdust and β with β Tdust-0.69, which is similar to what is seen in the local Universe. Finally, we report an increasing trend in the dust temperature as a function of redshift at a rate of 6.5 ±0.5 K/z for this 500 μm-selected sample. Based on this study, future prospects are outlined to further explore the evolution of dust temperature across cosmic time.
|
|
| 12. |
- Liu, Feng Yuan, et al.
(författare)
-
Dust and Cold Gas Properties of Starburst HyLIRG Quasars at z ∼ 2.5
- 2024
-
Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 964:2
-
Tidskriftsartikel (refereegranskat)abstract
- Some high-z active galactic nuclei (AGNs) are found to reside in extreme star-forming galaxies, such as hyperluminous infrared galaxies (HyLIRGs), with AGN-removed L IR of >1013 L ⊙. In this paper, we report NOEMA observations of six apparent starburst HyLIRGs associated with optical quasars at z ∼ 2-3 in the Stripe 82 field, to study their dust and molecular CO properties. Five out of the six candidates are detected with CO(4-3) or CO(5-4) emission, and four in the 2 mm dust continuum. Based on the linewidth- L CO ( 1 − 0 ) ′ diagnostics, we find that four galaxies are likely unlensed or weakly lensed sources. The molecular gas mass is in the range of μ M H 2 ∼ 0.8 - 9.7 × 10 10 M ⊙ (with α = 0.8 M ⊙ K km s − 1 pc 2 − 1 , where μ is the unknown possible gravitational magnification factor). We fit their spectral energy distributions, after including the observed 2 mm fluxes and upper limits, and estimate their apparent (uncorrected for possible lensing effects) star formation rates (μSFRs) to be ∼400-2500 M ⊙ yr−1, with a depletion time of ∼20-110 Myr. We notice interesting offsets, of ∼10-40 kpc spatially or ∼1000-2000 km s−1 spectroscopically, between the optical quasar and the millimeter continuum or CO emissions. The observed velocity shift is likely related to the blueshifted broad-emission-line region of quasars, though mergers or recoiling black holes are also possible causes, which can explain the spatial offsets and the high intrinsic star formation rates in the HyLIRG quasar systems.
|
|
| 13. |
- Muller, Sebastien, 1976, et al.
(författare)
-
Protonated acetylene in the z = 0.89 molecular absorber toward PKS 1830-211
- 2024
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 683
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first interstellar identification of protonated acetylene, C2H3+, a fundamental hydrocarbon, in the z = 0.89 molecular absorber toward the gravitationally lensed quasar PKS 1830-211. The molecular species is identified from clear absorption features corresponding to the 212-101 (rest frequency 494.034 GHz) and 111-000 (431.316 GHz) ground-state transitions of ortho and para forms of C2H3+, respectively, in ALMA spectra toward the southwestern image of PKS 1830-211, where numerous molecules, including other hydrocarbons, have already been detected. From the simple assumption of local thermodynamic equilibrium (LTE) with cosmic microwave background photons and an ortho-to-para ratio of three, we estimate a total C2H3+ column density of 2 × 1012 cm-2 and an abundance of 10-10 compared to H2. However, formation pumping could affect the population of metastable states, yielding a C2H3+ column density higher than the LTE value by a factor of a few. We explore possible routes to the formation of C2H3+, mainly connected to acetylene and methane, and find that the methane route is more likely in PDR environment. As one of the initial hydrocarbon building blocks, C2H3+ is thought to play an important role in astrochemistry, in particular in the formation of more complex organic molecules.
|
|
| 14. |
- Nesvadba, N. P.H., et al.
(författare)
-
Planck 's Dusty GEMS: VII. Atomic carbon and molecular gas in dusty starburst galaxies at z = 2 to 4
- 2019
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 624
-
Tidskriftsartikel (refereegranskat)abstract
- The bright 3 P 1 - 3 P 0 ([CI] 1-0) and 3 P 2 - 3 P 1 ([CI] 2-1) lines of atomic carbon are becoming more and more widely employed as tracers of the cold neutral gas in high-redshift galaxies. Here we present observations of these lines in the 11 galaxies of the set of Planck's Dusty GEMS, the brightest gravitationally lensed galaxies on the extragalactic submillimeter sky probed by the Planck satellite. We have [CI] 1-0 and [CI] 2-1 measurements for seven and eight of these galaxies, respectively, including four galaxies where both lines have been measured. We use our observations to constrain the gas excitation mechanism, excitation temperatures, optical depths, atomic carbon and molecular gas masses, and carbon abundances. Ratios of L CI /L FIR are similar to those found in the local universe, and suggest that the total cooling budget through atomic carbon has not significantly changed in the last 12 Gyr. Both lines are optically thin and trace 1 - 6 × 10 7 M of atomic carbon. Carbon abundances, X CI , are between 2.5 and 4 × 10 -5 , for an ultra-luminous infrared galaxy (ULIRG) CO-to-H 2 conversion factor of α CO = 0.8 M / [K km s -1 pc 2 ]. Ratios of molecular gas masses derived from [CI] 1-0 and CO agree within the measurement uncertainties for five galaxies, and agree to better than a factor of two for another two with [CI] 1-0 measurements, after carefully taking CO excitation into account. This does not support the idea that intense, high-redshift starburst galaxies host large quantities of "CO-dark" gas. These results support the common assumptions underlying most molecular gas mass estimates made for massive, dusty, high-redshift starburst galaxies, although the good agreement between the masses obtained with both tracers cannot be taken as independent confirmation of either α CO or X CI .
|
|
| 15. |
- Rex, M., et al.
(författare)
-
The far-infrared/submillimeter properties of galaxies located behind the Bullet cluster
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L13
-
Tidskriftsartikel (refereegranskat)abstract
- The Herschel Lensing Survey (HLS) takes advantage of gravitational lensing by massive galaxy clusters to sample a population of high-redshift galaxies which are too faint to be detected above the confusion limit of current far-infrared/submillimeter telescopes. Measurements from 100-500 mu m bracket the peaks of the far-infrared spectral energy distributions of these galaxies, characterizing their infrared luminosities and star formation rates. We introduce initial results from our science demonstration phase observations, directed toward the Bullet cluster (1E0657-56). By combining our observations with LABOCA 870 mu m and AzTEC 1.1 mm data we fully constrain the spectral energy distributions of 19 MIPS 24 mu m-selected galaxies which are located behind the cluster. We find that their colors are best fit using templates based on local galaxies with systematically lower infrared luminosities. This suggests that our sources are not like local ultra-luminous infrared galaxies in which vigorous star formation is contained in a compact highly dust-obscured region. Instead, they appear to be scaled up versions of lower luminosity local galaxies with star formation occurring on larger physical scales.
|
|
| 16. |
- Stanley, F., et al.
(författare)
-
Resolved CO(1-0) Emission and Gas Properties in Luminous Dusty Star-forming Galaxies at z = 2-4
- 2023
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 945:1
-
Tidskriftsartikel (refereegranskat)abstract
- We present the results of a survey of CO(1−0) emission in 14 infrared luminous dusty star-forming galaxies (DSFGs) at 2 < z < 4 with the NSF’s Karl G. Jansky Very Large Array. All sources are detected in 12CO(1−0), with an angular resolution of ∼1″. Seven sources show extended and complex structure. We measure CO luminosities of ( μ ) L CO ( 1 − 0 ) ′ = 0.4 - 2.9 × 10 11 K km s−1 pc2, and molecular gas masses of ( μ ) M H 2 = 1.3 - 8.6 × 10 11 M ⊙, where (μ) is the magnification factor. The derived molecular gas depletion times of t dep = 40-460 Myr, cover the expected range of both normal star-forming galaxies and starbursts. Compared to the higher −J CO transitions previously observed for the same sources, we find CO temperature brightness ratios of r 32/10 = 0.4-1.4, r 43/10 = 0.4-1.7, and r 54/10 = 0.3-1.3. We find a wide range of CO spectral line energy distributions (SLEDs), in agreement with other high-z DSFGs, with the exception of three sources that are most comparable to Cloverleaf and APM08279+5255. Based on radiative transfer modeling of the CO SLEDs we determine densities of n H 2 = 0.3 − 8.5 × 10 3 cm−3 and temperatures of T K = 100-200 K. Lastly, four sources are detected in the continuum, three have radio emission consistent with their infrared-derived star formation rates, while HerBS-70E requires an additional synchrotron radiation component from an active galactic nucleus. Overall, we find that even though the sample is similarly luminous in the infrared, by tracing the CO(1−0) emission a diversity of galaxy and excitation properties are revealed, demonstrating the importance of CO(1−0) observations in combination to higher-J transitions.
|
|
| 17. |
- Wang, R., et al.
(författare)
-
STAR FORMATION AND GAS KINEMATICS OF QUASAR HOST GALAXIES AT z similar to 6: NEW INSIGHTS FROM ALMA
- 2013
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 773:1
-
Tidskriftsartikel (refereegranskat)abstract
- We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the [C Pi] 158 mu m fine structure line and dust continuum emission from the host galaxies of five redshift 6 quasars. We also report complementary observations of 250 GHz dust continuum and CO (6-5) line emission from the z = 6.00 quasar SDSS J231038.88+185519.7 using the IRAM facilities. The ALMA observations were carried out in the extended array at 0.'' 7 resolution. We have detected the line and dust continuum in all five objects. The derived [C Pi] line luminosities are 1.6 x 10(9) to 8.7 x 10(9) L-circle dot and the [C Pi]-to-FIR luminosity ratios are 2.9-5.1 x 10(-4), which is comparable to the values found in other high-redshift quasar-starburst systems and local ultra-luminous infrared galaxies. The sources are marginally resolved and the intrinsic source sizes (major axis FWHM) are constrained to be 0.'' 3-0.'' 6 (i.e., 1.7-3.5 kpc) for the [C Pi] line emission and 0.'' 2-0.'' 4 (i.e., 1.2-2.3 kpc) for the continuum. These measurements indicate that there is vigorous star formation over the central few kpc in the quasar host galaxies. The ALMA observations also constrain the dynamical properties of the star-forming gas in the nuclear region. The intensity-weighted velocity maps of three sources show clear velocity gradients. Such velocity gradients are consistent with a rotating, gravitationally bound gas component, although they are not uniquely interpreted as such. Under the simplifying assumption of rotation, the implied dynamical masses within the [C Pi]-emitting regions are of order 10(10)-10(11) M-circle dot. Given these estimates, the mass ratios between the supermassive black holes and the spheroidal bulge are an order of magnitude higher than the mean value found in local spheroidal galaxies, which is in agreement with results from previous CO observations of high redshift quasars.
|
|
| 18. |
- Yang, C., et al.
(författare)
-
Submillimeter H 2 O and H 2 O + emission in lensed ultra- and hyper-luminous infrared galaxies at z ~ 2-4
- 2016
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 595, s. Art no A80-
-
Tidskriftsartikel (refereegranskat)abstract
- We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z ∼ 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern Extended Millimeter Array (NOEMA), we have detected 14 new H2O emission lines. These include five 321-312 ortho-H2O lines (Eup/k = 305 K) and nine J = 2 para-H2O lines, either 202-111 (Eup/k = 101 K) or 211-202 (Eup/k = 137 K). The apparent luminosities of the H2O emission lines are μLH2O ∼ 6-21 × 108 L⊙ (3 > μ > 15, where μ is the lens magnification factor), with velocity-integrated line fluxes ranging from 4-15 Jy km s-1. We have also observed CO emission lines using EMIR on the IRAM 30 m telescope in seven sources (most of those have not yet had their CO emission lines observed). The velocity widths for CO and H2O lines are found to be similar, generally within 1σ errors in the same source. With almost comparable integrated flux densities to those of the high-J CO line (ratios range from 0.4 to 1.1), H2O is found to be among the strongest molecular emitters in high-redshift Hy/ULIRGs. We also confirm our previously found correlation between luminosity of H2O(LH2O) and infrared (LIR) that LH2O ∼ LIR1:1-1:2, with our new detections. This correlation could be explained by a dominant role of far-infrared pumping in the H2O excitation. Modelling reveals that the far-infrared radiation fields have warm dust temperature Twarm ∼ 45-75 K, H2O column density per unit velocity interval NH2O/ΔV ≳ 0:3 × 1015 cm-2 km-1 s and 100 μm continuum opacity τ100 1 (optically thick), indicating that H2O is likely to trace highly obscured warm dense gas. However, further observations of J ≥ 4 H2O lines are needed to better constrain the continuum optical depth and other physical conditions of the molecular gas and dust. We have also detected H2O+ emission in three sources. A tight correlation between LH2O and LH2O+ has been found in galaxies from low to high redshift. The velocity-integrated flux density ratio between H2O+ and H2O suggests that cosmic rays generated by strong star formation are possibly driving the H2O+ formation. © 2016 ESO.
|
|
| 19. |
- Yang, Chentao, 1988, et al.
(författare)
-
SUNRISE: The rich molecular inventory of high-redshift dusty galaxies revealed by broadband spectral line surveys
- 2023
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 680
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the nature of high-redshift dusty galaxies requires a comprehensive view of their interstellar medium (ISM) and molecular complexity. However, the molecular ISM at high redshifts is commonly studied using only a few species beyond 12C16O, limiting our understanding. In this paper, we present the results of deep 3 mm spectral line surveys using the NOrthern Extended Millimeter Array (NOEMA) targeting two strongly lensed dusty galaxies observed when the Universe was less than 1.8 Gyr old: APM 08279+5255, a quasar at redshift z = 3.911, and NCv1.143 (H-ATLAS J125632.7+233625), a z = 3.565 starburst galaxy. The spectral line surveys cover rest-frame frequencies from about 330 to 550 GHz for both galaxies. We report the detection of 38 and 25 emission lines in APM 08279+5255 and NCv1.143, respectively. These lines originate from 17 species, namely CO, 13CO, C18O, CN, CCH, HCN, HCO+, HNC, CS, C34S, H2O, H3O+, NO, N2H+, CH, c-C3H2, and the vibrationally excited HCN and neutral carbon. The spectra reveal the chemical richness and the complexity of the physical properties of the ISM. By comparing the spectra of the two sources and combining the analysis of the molecular gas excitation, we find that the physical properties and the chemical imprints of the ISM are different: the molecular gas is more excited in APM 08279+5255, which exhibits higher molecular gas temperatures and densities compared to NCv1.143; the molecular abundances in APM 08279+5255 are akin to the values of local active galactic nuclei (AGN), showing boosted relative abundances of the dense gas tracers that might be related to high-temperature chemistry and/or the X-ray-dominated regions, while NCv1.143 more closely resembles local starburst galaxies. The most significant differences between the two sources are found in H2O: the 448 GHz ortho-H2O(423 - 330) line is significantly brighter in APM 08279+5255, which is likely linked to the intense far-infrared radiation from the dust powered by AGN. Our astrochemical model suggests that, at such high column densities, far-ultraviolet radiation is less important in regulating the ISM, while cosmic rays (and/or X-rays and shocks) are the key players in shaping the molecular abundances and the initial conditions of star formation. Both our observed CO isotopologs line ratios and the derived extreme ISM conditions (high gas temperatures, densities, and cosmic-ray ionization rates) suggest the presence of a top-heavy stellar initial mass function. From the ~330-550 GHz continuum, we also find evidence of nonthermal millimeter flux excess in APM 08279+5255 that might be related to the central supermassive black hole. Such deep spectral line surveys open a new window into the physics and chemistry of the ISM and the radiation field of galaxies in the early Universe.
|
|
