| 1. |
- Drouart, Guillaume, 1987, et al.
(author)
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Disentangling star formation and AGN activity in powerful infrared luminous radio galaxies at 1
- 2016
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 593, s. Art. no. A109-
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Journal article (peer-reviewed)abstract
- High-redshift radio galaxies present signs of both star formation and AGN activity, making them ideal candidates to investigate the connection and coevolution of AGN and star formation in the progenitors of present-day massive galaxies. We make use of a sample of 11 powerful radio galaxies spanning 1
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| 2. |
- Drouart, Guillaume, 1987, et al.
(author)
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Rapidly growing black holes and host galaxies in the distant Universe from the Herschel Radio Galaxy Evolution Project
- 2014
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 566
-
Journal article (peer-reviewed)abstract
- We present results from a comprehensive survey of 70 radio galaxies at redshifts 1 10(12) L-circle dot) or hyper-luminous (L-tot(IR) > 10(13) L-circle dot) infrared galaxies. We fit the infrared SEDs with a set of empirical templates which represent dust heated by a variety of starbursts (SB) and by an active galactic nucleus (AGN). We find that the SEDs of radio galaxies require the dust to be heated by both AGN and SB, but the luminosities of these two components are not strongly correlated. Assuming empirical relations and simple physical assumptions, we calculate the star formation rate (SFR), the black hole mass accretion rate ((M) over dot(BH)), and the black hole mass (M-BH) for each radio galaxy. We find that the host galaxies and their black holes are growing extremely rapidly, having SFR approximate to 100-5000 M-circle dot yr(-1) and. (M) over dot(BH) approximate to 1-100 M(circle dot)yr(-1). The mean specific SFRs (sSFR) of radio galaxies at z > 2 : 5 are higher than the sSFR of typical star forming galaxies over the same redshift range, but are similar or perhaps lower than the galaxy population for radio galaxies at z
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| 3. |
- Emonts, B., et al.
(author)
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A CO-rich merger shaping a powerful and hyperluminous infrared radio galaxy at z=2: the Dragonfly Galaxy
- 2015
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In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 451:1, s. 1025-1035
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Journal article (peer-reviewed)abstract
- In the low-redshift Universe, the most powerful radio sources are often associated with gasrich galaxy mergers or interactions. We here present evidence for an advanced, gas-rich ('wet') merger associated with a powerful radio galaxy at a redshift of z similar to 2. This radio galaxy, MRC 0152-209, is the most infrared-luminous high-redshift radio galaxy known in the Southern hemisphere. Using the Australia Telescope Compact Array, we obtained highresolution CO(1-0) data of cold molecular gas, which we complement with Hubble Space Telescope (HS7)IWide Field Planetaiy Camera 2 (WFPC2) imaging and William Herschel Telescope long-slit spectroscopy. We find that, while roughly M-H2 x 10(10) Me of molecular gas coincides with the central host galaxy, another M-H2 similar to 3 x 10(10) Me is spread across a total extent of'-60 kpc. Most of this widespread CO(1-0) appears to follow prominent tidal features visible in the rest-frame near-UV HSTIWFPC2 imaging. Lya emission shows an excess over He II, but a deficiency over LIR, which is likely the result of photoionization by enhanced but very obscured star formation that was triggered by the merger. In terms of feedback, the radio source is aligned with widespread CO(1-0) emission, which suggests that there is a physical link between the propagating radio jets and the presence of cold molecular gas on scales of the galaxy's halo. Its optical appearance, combined with the transformational stage at which we witness the evolution of MRC 0152-209, leads us to adopt the name 'Dragonfly Galaxy'.
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| 4. |
- Emonts, B., et al.
(author)
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The Dragonfly Galaxy: II. ALMA unveils a triple merger and gas exchange in a hyper-luminous radio galaxy at z = 2
- 2015
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 584
-
Journal article (peer-reviewed)abstract
- The Dragonfly Galaxy (MRC 0152-209), at redshift z similar to 2, is one of the most vigorously star-forming radio galaxies in the Universe. What triggered its activity? We present ALMA Cycle 2 observations of cold molecular CO(6 5) gas and dust, which reveal that this is likely a gas-rich triple merger. It consists of a close double nucleus (separation similar to 4 kpc) and a weak CO-emitter at similar to 10 kpc distance, all of which have counterparts in HST/NICMOS imagery. The hyper-luminous starburst and powerful radio-AGN were triggered at this precoalescent stage of the merger. The CO(6-5) traces dense molecular gas in the central region, and complements existing CO(1-0) data, which reveal more widespread tidal debris of cold gas. We also find similar to 10(10) M-circle dot of molecular gas with enhanced excitation at the highest velocities. At least 20-50% of this high-excitation, high-velocity gas shows kinematics that suggests it is being displaced and redistributed within the merger, although with line-of-sight velocities of vertical bar v vertical bar < 500 km s(-1), this gas will probably not escape the system. The processes that drive the redistribution of cold gas are likely related to either the gravitational interaction between two kpc-scale discs, or starburst/AGN-driven outflows. We estimate that the rate at which the molecular gas is redistributed is at least. M similar to 1200 +/- 500 M-circle dot yr(-1), and could perhaps even approach the star formation rate of similar to 3000 +/- 800 M-circle dot yr(-1). The fact that the gas depletion and gas redistribution timescales are similar implies that dynamical processes can be important in the evolution of massive high-z galaxies.
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| 5. |
- Fan, Lulu, 1982, et al.
(author)
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ALMA Detections of CO Emission in the Most Luminous, Heavily Dust-obscured Quasars at z > 3
- 2018
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In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 856:1
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Journal article (peer-reviewed)abstract
- We report the results of a pilot study of CO(4 - 3) emission line of three Wide-field Infrared Survey Explorer (WISE)-selected hyper-luminous, dust-obscured quasars (QSOs) with sensitive ALMA Band 3 observations. These obscured QSOs with L bol > 10 14 L o; are among the most luminous objects in the universe. All three QSO hosts are clearly detected both in continuum and in CO(4 - 3) emission line. Based on CO(4 - 3) emission line detection, we derive the molecular gas masses (∼10 10-11 M o; ), suggesting that these QSOs are gas-rich systems. We find that the obscured QSOs in our sample follow the similar relation as unobscured QSOs at high redshifts. We also find the complex velocity structures of CO(4 - 3) emission line, which provide the possible evidence for a gas-rich merger in W0149+2350 and possible molecular outflow in W0220+0137 and W0410-0913. Massive molecular outflow can blow away the obscured interstellar medium and make obscured QSOs evolve toward the UV/optical bright, unobscured phase. Our result is consistent with the popular active galactic nucleus (AGN) feedback scenario involving the co-evolution between the supermassive black holes and host galaxy.
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| 6. |
- Fan, Lulu, 1982, et al.
(author)
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Infrared Spectral Energy Distribution Decomposition of Wise-Selected, Hyperluminous Hot Dust-Obscured Galaxies
- 2016
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In: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 823:2, s. Art. no. 107-
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Journal article (peer-reviewed)abstract
- We utilize a Bayesian approach to fit the observed mid-IR-To-submillimeter/millimeter spectral energy distributions (SEDs) of 22 WISE-selected and submillimeter-detected, hyperluminous hot dust-obscured galaxies (Hot DOGs), with spectroscopic redshift ranging from 1.7 to 4.6. We compare the Bayesian evidence of a torus plusgraybody (Torus+GB) model with that of a torus-only (Torus) model and find that the Torus+GB model has higher Bayesian evidence for all 22 Hot DOGs than the torus-only model, which presents strong evidence in favor of the Torus+GB model. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are as follows. (1) Hot DOGs in our submillimeter-detected sample are hyperluminous , with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, contributing on average of total IR luminosity. (2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submillimeter at rest frame, while it is very similar to that of QSOs at , suggesting that the heating sources of Hot DOGs should be buried AGNs. (3) Hot DOGs have high dust temperatures ( K) and high IR luminosity of cold dust. The relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust temperature, rather than dust mass. Hot DOGs have lower dust masses than submillimeter galaxies (SMGs) and QSOs within a similar redshift range. Both high IR luminosity of cold dust and relatively low dust mass in Hot DOGs can be expected by their relatively high dust temperatures. (4) Hot DOGs have high dust-covering factors (CFs), which deviate from the previously proposed trend of the dust CF decreasing with increasing bolometric luminosity. Finally, we can reproduce the observed properties in Hot DOGs by employing a physical model of galaxy evolution. This result suggests that Hot DOGs may lie at or close to peaks of both star formation and black hole growth histories, and represent a transit phase during the evolutions of massive galaxies, transforming them from the dusty starburst-dominated phase to the optically bright QSO phase.
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| 7. |
- Fogasy, Judit, 1988, et al.
(author)
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ALMA detects molecular gas in the halo of the powerful radio galaxy TXS 0828+193
- 2021
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In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 501:4, s. 5973-5980
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Journal article (peer-reviewed)abstract
- Both theoretical and observational results suggest that high-redshift radio galaxies (HzRGs) inhabit overdense regions of the universe and might be the progenitors of local, massive galaxies residing in the centre of galaxy clusters. In this paper, we present CO(3-2) line observations of the HzRG TXS 0828+193 (z = 2.57) and its environment using the Atacama Large Millimeter/submillimeter Array. In contrast to previous observations, we detect CO emission associated with the HzRG and derive a molecular gas mass of $(0.9\pm 0.3)\times 10^{10}\, \rm M_{\odot }$. Moreover, we confirm the presence of a previously detected off-source CO emitting region (companion #1), and detect three new potential companions. The molecular gas mass of each companion is comparable to that of the HzRG. Companion #1 is aligned with the axis of the radio jet and has stellar emission detected by Spitzer. Thus, this source might be a normal star-forming galaxy or alternatively a result of jet-induced star formation. The newly found CO sources do not have counterparts in any other observing band and could be high-density clouds in the halo of TXS 0828+193 and thus potentially linked to the large-scale filamentary structure of the cosmic web.
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| 8. |
- Fogasy, Judit, 1988, et al.
(author)
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On the frequency of star-forming galaxies in the vicinity of powerful AGNs: The case of SMM J04135+10277
- 2017
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 597
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Journal article (peer-reviewed)abstract
- Context. In the last decade several massive molecular gas reservoirs were found 108M, and 0.3% have at least one highly star-forming companion (SFR> 100 M yr-1). Conclusions. Our results suggest that quasar-gas-rich companion galaxy systems are common phenomena in the early Universe and the high incidence of companions makes the study of such systems crucial to understand the growth and hierarchical build-up of galaxies and black holes.
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| 9. |
- Fogasy, Judit, 1988, et al.
(author)
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SMM J04135+10277: a distant QSO-starburst system caught by ALMA
- 2020
-
In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 493:3, s. 3744-3756
-
Journal article (peer-reviewed)abstract
- The gas content of galaxies is a key factor for their growth, starting from star formation and black hole accretion to galaxy mergers. Thus, characterizing its properties through observations of tracers like the CO emission line is of big importance in order to understand the bigger picture of galaxy evolution. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of dust continuum, CO(5-4) and CO(8-7) line emission in the quasar-star-forming companion system SMM J04135+10277 (z = 2.84). Earlier low-J CO studies of this system found a huge molecular gas reservoir associated with the companion galaxy, while the quasar appeared gas-poor. Our CO observations revealed that the host galaxy of the quasar is also gas-rich, with an estimated molecular gas mass of ∼ (0.7-2.3)× 10^{10} M_{☉}. The CO line profiles of the companion galaxy are very broad (∼ 1000 km s^{-1}), and show signs of rotation of a compact, massive system. In contrast to previous far-infrared observations, we resolve the continuum emission and detect both sources, with the companion galaxy dominating the dust continuum and the quasar having a ∼ 25{{ per cent}} contribution to the total dust emission. By fitting the infrared spectral energy distribution of the sources with MR-MOOSE and empirical templates, the infrared luminosities of the quasar and the companion are in the range of L_{IR, QSO}∼ (2.1-9.6)× 10^{12} L_{☉} and L_{IR, Comp.}∼ (2.4-24)× 10^{12} L_{☉}, while the estimated star formation rates are ∼ 210-960 and ∼ 240-2400 M_{☉} yr^{-1}, respectively. Our results demonstrate that non-detection of low-J CO transition lines in similar sources does not necessarily imply the absence of massive molecular gas reservoir but that the excitation conditions favour the excitation of high-J transitions.
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| 10. |
- Gullberg, B., et al.
(author)
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ALMA finds dew drops in the dusty spider's web
- 2016
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 591
-
Journal article (peer-reviewed)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
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| 11. |
- Gullberg, B., et al.
(author)
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The mysterious morphology of MRC0943-242 as revealed by ALMA and MUSE
- 2016
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 586
-
Journal article (peer-reviewed)abstract
- © 2016 ESO. We present a pilot study of the z = 2.923 radio galaxy MRC0943-242, where we combine information from ALMA and MUSE data cubes for the first time. Even with modest integration times, we disentangle the AGN and starburst dominated components. These data reveal a highly complex morphology as the AGN, starburst, and molecular gas components show up as widely separated sources in dust continuum, optical continuum, and CO line emission observations. CO(1-0) and CO(8-7) line emission suggest that there is a molecular gas reservoir offset from both the dust and the optical continuum that is located ∼90 kpc from the AGN. The UV line emission has a complex structure in emission and absorption. The line emission is mostly due to a large scale ionisation cone energised by the AGN, and a Lyα emitting bridge of gas between the radio galaxy and a heavily star-forming set of components. Strangely, the ionisation cone has no Lyα emission. We find this is due to an optically thick layer of neutral gas with unity covering fraction spread out over a region of at least ∼100 kpc from the AGN. Other less thick absorption components are associated with Lyα emitting gas within a few tens of kpc from the radio galaxy and are connected by a bridge of emission. We speculate that this linear structure of dust, Lyα and CO emission, and the redshifted absorption seen in the circum nuclear region may represent an accretion flow feeding gas into this massive AGN host galaxy.
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| 12. |
- Knudsen, Kirsten Kraiberg, 1976, et al.
(author)
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C II emission in z similar to 6 strongly lensed, star-forming galaxies
- 2016
-
In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966 .- 1745-3925 .- 1745-3933. ; 462:1, s. L6-L10
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Journal article (peer-reviewed)abstract
- The far-infrared fine-structure line [C II] at 1900.5 GHz is known to be one of the brightest cooling lines in local galaxies, and therefore it has been suggested to be an efficient tracer for star formation in very high redshift galaxies. However, recent results for galaxies at z > 6 have yielded numerous non-detections in star-forming galaxies, except for quasars and submillimetre galaxies. We report the results of ALMA observations of two lensed, star-forming galaxies at z = 6.029 and z = 6.703. The galaxy A383-5.1 (star formation rate [SFR] of 3.2 M-circle dot yr(-1) and magnification of mu = 11.4 +/- 1.9) shows a line detection with L-[C II] = 8.9 x 10(6) L-circle dot, making it the lowest L-[C II] detection at z > 6. For MS0451-H (SFR = 0.4 M-circle dot yr(-1) and mu = 100 +/- 20) we provide an upper limit of L-[C II] 6; however, other effects could also play a role in terms of decreasing L-[CII]. The detection of A383-5.1 is encouraging and suggests that detections are possible, but much fainter than initially predicted.
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| 13. |
- Lindroos, Lukas, 1986, et al.
(author)
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Estimating sizes of faint, distant galaxies in the submillimetre regime
- 2016
-
In: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 462:2, s. 1192-1202
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Journal article (peer-reviewed)abstract
- We measure the sizes of redshift similar to 2 star-forming galaxies by stacking data from the At-acama Large Millimeter/submillimeter Array (ALMA). We use a uv-stacking algorithm in combination with model fitting in the uv-domain and show that this allows for robust measures of the sizes of marginally resolved sources. The analysis is primarily based on the 344 GHz ALMA continuum observations centred on 88 submillimetre galaxies in the LABOCA ECDFS Submillimeter Survey (ALESS). We study several samples of galaxies at z approximate to 2 with M-* approximate to 5 x 10(10) M-circle dot, selected using near-infrared photometry (distant red galaxies, extremely red objects, sBzK-galaxies, and galaxies selected on photometric redshift). We find that the typical sizes of these galaxies are similar to 0.6 arcsec which corresponds to similar to 5 kpc at z = 2, this agrees well with the median sizes measured in the near-infrared z band (similar to 0.6 arcsec). We find errors on our size estimates of similar to 0.1-0.2 arcsec, which agree well with the expected errors for model fitting at the given signal-to-noise ratio. With the uv-coverage of our observations (18-160 m), the size and flux density measurements are sensitive to scales out to 2 arcsec. We compare this to a simulated ALMA Cycle 3 data set with intermediate length baseline coverage, and we find that, using only these baselines, the measured stacked flux density would be an order of magnitude fainter. This highlights the importance of short baselines to recover the full flux density of high-redshift galaxies.
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| 14. |
- Rocca-Volmerange, B., et al.
(author)
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SUPERNOVA REMNANT MASS ACCUMULATED DURING THE STAR FORMATION HISTORY OF THE z=3.8 RADIO GALAXIES 4C41.17 AND TN J2007-1316
- 2015
-
In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 803:1
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Journal article (peer-reviewed)abstract
- In this paper, we show that the supernova remnant (SNR) masses accumulated from core-collapse supernovae (SNe) along the star formation history of two powerful z = 3.8 radio galaxies, 4C41.17 and TN J2007-1316, reach up to ?-109 MG, which is comparable to supermassive black hole (SMBH) masses measured from the SDSS sample at similar redshifts. The SNR mass is measured from the already exploded SN mass after subtraction of ejecta while the mass of still luminous stars fits at best the observed spectral energy distribution, continuously extended to the optical Spitzer Herschel submm domains, with the help of the galaxy evolution model Pegase.3. For recent and old stellar populations, SNR masses vary about 10(9-10) M-circle dot and the SNR to star mass ratio between 1% and 0.1% is comparable to the observed low-z SMBH to star mass ratio. For the template radio galaxy 4C41.17, SNR and stellar population masses estimated from large aperture (>4 arcsec = 30 kpc) observations are compatible, within one order of mass, with the total mass of multiple optical Hubble Space Telescope (700 pc) structures associated with VLA radio emissions, both at 0.1 arcsec. Probing the SNR accretion fueling central black holes is a simple explanation for SMBH growth, which requires the physics of star formation and stellar and galaxy dynamics with consequences for various processes (quenching, mergers, negative feedback) and is also a key to the bulge SMBH relation.
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| 15. |
- Rodriguez, M. I., et al.
(author)
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The molecular gas content of ULIRG type 2 quasars at z
- 2014
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 565
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Journal article (peer-reviewed)abstract
- We present new results of CO(1-0) spectroscopic observations of four Sloan Digital Sky Survey (SDSS) type 2 quasars (QSO2) at z similar to 0.3, observed with the 30-m IRAM radio telescope. The QSO2 have infrared luminosities in the ultra-luminous infrared galaxies (ULIRG) regime. We confirm the CO(1-0) detection in one of our four QSO2, SDSS J1543-00, with L-CO' and M-H2 (1.2 +/- 0.2) x 10(10) K km s(-1) pc(2) and (9.4 +/- 1.4) x 10(9) M-circle dot, respectively. The full width at half maximum (FWHM) of the CO(1-0) line is =575 +/- 102 km s(-1). No CO(1-0)) emission is detected in SDSS J0903+02, SDSS j1337-01, SDSS j1520-01 above 3 sigma, yielding upper limits on M(H-2) similar to 9.6, 4.3 and 5.1 x 10(9) M-circle dot, respectively. We expand previous studies of the molecular gas content of intermediate z QSO2 into the ULIRG regime. Taking into account nine QSO2 at z similar to 0.3-1.0 from the literature, we discuss the location of the 13 ULIRG QSO2 at z
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