| 1. |
- Blanton, Michael R., et al.
(författare)
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Sloan Digital Sky Survey IV : Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
- 2017
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Ingår i: Astronomical Journal. - : IOP Publishing Ltd. - 0004-6256 .- 1538-3881. ; 154:1
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Tidskriftsartikel (refereegranskat)abstract
- We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and. high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z similar to 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z similar to 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs. and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the. Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.
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| 2. |
- Cicone, Claudia, et al.
(författare)
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Enhanced UV radiation and dense clumps in the molecular outflow of Mrk 231
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 633
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Tidskriftsartikel (refereegranskat)abstract
- We present interferometric observations of the CN(1-0) line emission in Mrk 231 and combine them with previous observations of CO and other H-2 gas tracers to study the physical properties of the massive molecular outflow. We find a strong boost of the CN/CO(1-0) line luminosity ratio in the outflow of Mrk 231, which is unprecedented compared to any other known Galactic or extragalactic astronomical source. For the dense gas phase in the outflow traced by the HCN and CN emissions, we infer X-CN equivalent to [CN]/[H-2]> X-HCN by at least a factor of three, with H-2 gas densities of n(H2) similar to 10(5-6)& x2006;cm(-3). In addition, we resolve for the first time narrow spectral features in the HCN(1-0) and HCO+(1-0) high-velocity line wings tracing the dense phase of the outflow. The velocity dispersions of these spectral features, sigma(v) similar to 7-20 km s(-1), are consistent with those of massive extragalactic giant molecular clouds detected in nearby starburst nuclei. The H-2 gas masses inferred from the HCN data are quite high, M-mol similar to 0.3-5 x 10(8) M-circle dot. Our results suggest that massive complexes of denser molecular gas survive embedded into the more diffuse H-2 phase of the outflow, and that the chemistry of these outflowing dense clouds is strongly affected by UV radiation.
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| 3. |
- Roederer, Ian U., et al.
(författare)
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The discovery space of ELT-ANDES. Stars and stellar populations
- 2024
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Ingår i: Experimental Astronomy. - 0922-6435. ; 57:2
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Tidskriftsartikel (refereegranskat)abstract
- The ArmazoNes high Dispersion Echelle Spectrograph (ANDES) is the optical and near-infrared high-resolution echelle spectrograph envisioned for the Extremely Large Telescope (ELT). We present a selection of science cases, supported by new calculations and simulations, where ANDES could enable major advances in the fields of stars and stellar populations. We focus on three key areas, including the physics of stellar atmospheres, structure, and evolution; stars of the Milky Way, Local Group, and beyond; and the star-planet connection. The key features of ANDES are its wide wavelength coverage at high spectral resolution and its access to the large collecting area of the ELT. These features position ANDES to address the most compelling questions and potentially transformative advances in stellar astrophysics of the decades ahead, including questions which cannot be anticipated today.
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| 4. |
- Trussler, James A. A., et al.
(författare)
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On the observability and identification of Population III galaxies with JWST
- 2023
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 525:4, s. 5328-5352
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Tidskriftsartikel (refereegranskat)abstract
- We utilize theoretical models of Population III stellar + nebular spectra to investigate the prospects of observing and accurately identifying Population III galaxies with JWST using both deep imaging and spectroscopy. We investigate a series of different colour cuts, finding that a combination of NIRCam and MIRI photometry through the F444W-F560W, F560W-F770W colours offers the most robust identifier of potential z = 8 Pop III candidates. We calculate that NIRCam will have to reach similar to 28.5-30.0 AB mag depths (1-20 h), and MIRI F560W must reach similar to 27.5-29.0 AB mag depths (10-100 h) to achieve 5 sigma continuum detections of M-* = 10(6) M-circle dot Pop III galaxies at z = 8. We also discuss the prospects of identifying Pop III candidates through slitless and NIRSpec spectroscopic surveys that target Ly alpha, H beta, and/or He II lambda 1640. We find small differences in the H beta rest-frame equivalent width (EW) between Pop III and non-Pop III galaxies, rendering this diagnostic likely impractical. Instead, we find that the detection of high EW He II lambda 1640 emission will serve as the definitive Pop III identifier, requiring (ultra-)deep integrations (5-150 h) with NIRSpec/G140M for M-* = 10(6) M-circle dot Pop III galaxies at z = 8. However, MIRI F770W detections of Pop III galaxies will require substantial gravitational lensing (mu = 10) and/or fortuitous imaging of exceptionally massive (M-* = 10(7) M-circle dot) Pop III galaxies. Thus, NIRCam medium-band imaging surveys that can search for high EW He II lambda 1640 emitters in photometry may perhaps be a viable alternative for finding Pop III candidates.
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| 5. |
- Veilleux, Sylvain, et al.
(författare)
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Cool outflows in galaxies and their implications
- 2020
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Ingår i: Astronomy and Astrophysics Review. - : Springer Science and Business Media LLC. - 0935-4956 .- 1432-0754. ; 28:1
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Forskningsöversikt (refereegranskat)abstract
- Neutral-atomic and molecular outflows are a common occurrence in galaxies, near and far. They operate over the full extent of their galaxy hosts, from the innermost regions of galactic nuclei to the outermost reaches of galaxy halos. They carry a substantial amount of material that would otherwise have been used to form new stars. These cool outflows may have a profound impact on the evolution of their host galaxies and environments. This article provides an overview of the basic physics of cool outflows, a comprehensive assessment of the observational techniques and diagnostic tools used to characterize them, a detailed description of the best-studied cases, and a more general discussion of the statistical properties of these outflows in the local and distant universe. The remaining outstanding issues that have not yet been resolved are summarized at the end of the review to inspire new research directions.
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