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- ID:
- ivo://CDS.VizieR/J/ApJ/699/782
- Title:
- High-redshift SDSS-DR5 QSOs
- Short Name:
- J/ApJ/699/782
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify a sample of 74 high-redshift quasars (z>3) with weak UV emission lines from the Fifth Data Release of the Sloan Digital Sky Survey and present infrared, optical, and radio observations of a subsample of four objects at z>4. These weak emission-line quasars (WLQs) constitute a prominent tail of the Ly{alpha}+NV equivalent width distribution, and we compare them to quasars with more typical emission-line properties and to low-redshift active galactic nuclei with weak/absent emission lines, namely BL Lac objects. We find that WLQs exhibit hot (T~1000K) thermal dust emission and have rest-frame 0.1-5um spectral energy distributions that are quite similar to those of normal quasars. The variability, polarization, and radio properties of WLQs are also different from those of BL Lacs, making continuum boosting by a relativistic jet an unlikely physical interpretation.
- ID:
- ivo://CDS.VizieR/J/ApJ/602/571
- Title:
- High-redshift supernovae IRZ fluxes
- Short Name:
- J/ApJ/602/571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric and spectroscopic observations of 23 high-redshift supernovae (SNe) spanning a range of z=0.34-1.03, nine of which are unambiguously classified as Type Ia. These SNe were discovered during the IfA Deep Survey, which began in 2001 September and observed a total of 2.5deg^2^ to a depth of approximately m~25-26 in RIZ over 9-17 visits, typically every 1-3 weeks for nearly 5 months, with additional observations continuing until 2002 April.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/8
- Title:
- High resolution NIR observations of z>~1 galaxies
- Short Name:
- J/ApJ/864/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present images taken using the Gemini South Adaptive Optics Imager (GSAOI) with the Gemini Multi-conjugate Adaptive Optics System (GeMS) in three 2arcmin^2^ fields in the Spitzer Extragalactic Representative Volume Survey. These GeMS/GSAOI observations are among the first ~0.1" resolution data in the near-infrared spanning extragalactic fields exceeding 1.5' in size. We use these data to estimate galaxy sizes, obtaining results similar to those from studies with the Hubble Space Telescope, though we find a higher fraction of compact star-forming galaxies at z>2. To disentangle the star-forming galaxies from active galactic nuclei (AGNs), we use multiwavelength data from surveys in the optical and infrared, including far-infrared data from Herschel, as well as new radio continuum data from the Australia Telescope Compact Array and Very Large Array. We identify ultraluminous infrared galaxies (ULIRGs) at z~1-3, which consist of a combination of pure starburst galaxies and AGN/starburst composites. The ULIRGs show signs of recent merger activity, such as highly disturbed morphologies and include a rare candidate triple-AGN. We find that AGNs tend to reside in hosts with smaller scale sizes than purely star-forming galaxies of similar infrared luminosity. Our observations demonstrate the potential for MCAO to complement the deeper galaxy surveys to be made with the James Webb Space Telescope.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/156
- Title:
- High-z galaxy candidates in the HFF cluster fields
- Short Name:
- J/ApJ/862/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Acting as powerful gravitational lenses, the strong lensing galaxy clusters of the deep Hubble Frontier Fields (HFF) program permit access to lower-luminosity galaxies lying at higher redshifts than hitherto possible. We analyzed the HFF to measure the volume density of Lyman-break galaxies at z>4.75 by identifying a complete and reliable sample up to z~10. A marked deficit of such galaxies was uncovered in the highly magnified regions of the clusters relative to their outskirts, implying that the magnification of the sky area dominates over additional faint galaxies magnified above the flux limit. This negative magnification bias is consistent with a slow rollover at the faint end of the UV luminosity function and it indicates a preference for Bose-Einstein condensate dark matter with a light boson mass of m_B_~10^-22^eV over standard cold dark matter. We emphasize that measuring the magnification bias requires no correction for multiply-lensed images (with typically three or more images per source), whereas directly reconstructing the luminosity function will lead to an overestimate unless such images can be exhaustively matched up, especially at the faint end that is only accessible in the strongly lensed regions. In addition, we detected a distinctive downward transition in galaxy number density at z>~8, which may be linked to the relatively late reionization reported by Planck. Our results suggests that JWST will likely peer into an "abyss" with essentially no galaxies detected in deep NIR imaging at z>10.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/3740
- Title:
- High-z LAEs and LBGs in SHARDS survey
- Short Name:
- J/MNRAS/478/3740
- Date:
- 11 Mar 2022 14:56:32
- Publisher:
- CDS
- Description:
- We have undertaken a comprehensive search for both Lyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) in the Survey for High-z Absorption Red and Dead Sources (SHARDS) Survey of the Great Observatories Origins Deep Survey North field. SHARDS is a deep imaging survey, made with the 10.4m Gran Telescopio Canarias, employing 25 medium band filters in the range from 500 to 941nm. This is the first time that both LAEs and LBGs are surveyed simultaneously in a systematic way in a large field. We draw a sample of 1558 sources; 528 of them are LAEs. Most of the sources (1434) show rest-frame UV continua. A minority of them (124) are pure LAEs with virtually no continuum detected in SHARDS. We study these sources from z~3.35 up to z~6.8, well into the epoch of reionization. Note that surveys done with just one or two narrow band filters lack the possibility to spot the rest-frame UV continuum present in most of our LAEs. We derive redshifts, star formation rates, Ly{alpha} equivalent widths, and luminosity functions (LFs). Grouping within our sample is also studied, finding 92 pairs or small groups of galaxies at the same redshift separated by less than 60 comoving kpc. In addition, we relate 87 and 55 UV-selected objects with two known overdensities at z=4.05 and z=5.198, respectively. Finally, we show that surveys made with broad-band filters are prone to introduce many unwanted sources (~20 per cent interlopers), which means that previous studies may be overestimating the calculated LFs, specially at the faint end.
- ID:
- ivo://CDS.VizieR/J/ApJ/764/9
- Title:
- High-z MgII absorption QSOs with FIRE. II.
- Short Name:
- J/ApJ/764/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of HI and metals for 110 MgII absorption systems discovered at 1.98<=z<=5.33 in the infrared spectra of high-redshift QSOs. Using new measurements of rest-frame UV lines from optical spectra of the same targets, we compare the high-redshift sample with carefully constructed low-redshift control samples from the literature to study evolutionary trends from z=0-->5.33 (>12Gyr). We observe a significant strengthening in the characteristic N(HI) for fixed MgII equivalent width as one moves toward higher redshift. Indeed, at our sample's mean <Z>=3.402, all MgII systems are either damped Ly{alpha} absorbers (DLAs) or sub-DLAs, with 40.7% of systems exceeding the DLA threshold (compared to 16.7% at <Z>=0.927). We set lower limits on the metallicity of the MgII systems where we can measure HI; these results are consistent with the full DLA population. The classical MgII systems (W({lambda}2796)_0_=0.3-1.0{AA}), which preferentially associate with sub-DLAs, are quite metal rich at ~0.1 solar. We applied quantitative classification metrics to our absorbers to compare with low-redshift populations, finding that weak systems are similar to classic MgII absorbers at low redshift. The strong systems either have very large MgII and FeII velocity spreads implying non-virialized dynamics or are more quiescent DLAs. There is tentative evidence that the kinetically complex systems evolve in similar fashion to the global star formation rate. We speculate that if weaker MgII systems represent accreting gas as suggested by recent studies of galaxy-absorber inclinations, then their high metal abundance suggests re-accretion of recently ejected material rather than first-time infall from the metal-poor intergalactic medium, even at early times.
- ID:
- ivo://CDS.VizieR/J/ApJ/594/1
- Title:
- High-z supernovae VRI mag and distances
- Short Name:
- J/ApJ/594/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The High-z Supernova Search Team has discovered and observed eight new supernovae in the redshift interval z=0.3-1.2. These independent observations, analyzed by similar but distinct methods, confirm the results of Riess (1998AJ....116.1009R) and Perlmutter (1999ApJ...517..565P) and coworkers that supernova luminosity distances imply an accelerating universe.
- ID:
- ivo://CDS.VizieR/J/A+A/319/67
- Title:
- HI observations of dwarf galaxies in voids
- Short Name:
- J/A+A/319/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report HI-observations of a sample of 43 optically selected galaxies from the Heidelberg-void project. Only emission-line galaxies have been selected. The HI-detection rate was 67%. The observed sample is a mix in late-type morphology objects with a spread in luminosity. They were compared to other samples with similar selection effects and mixtures. The detected galaxies have a high HI content and their M_HI_/L_B_ values are systematically higher than expected from a local field comparison sample. Especially, for the 10 dwarfs in our sample (8.2<=logL_B_<=9.2) which appear to be highly isolated, a mean M_HI_/L_B_=1.8 was derived which is higher than for all comparison samples, including those with the same restricted luminosity range. We discuss a trend in our data between the relative HI-content and the surrounding galaxy density holding from very high densities (Virgo-cluster) to the very isolated objects at the rims of the voids. We also present HI observations of 7 HII-galaxies of the University of Michigan (UM) sample.
- ID:
- ivo://CDS.VizieR/J/AJ/127/3235
- Title:
- HIRES atlas of all RBGS galaxies
- Short Name:
- J/AJ/127/3235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution 12, 25, 60, and 100{mu}m images of 106 interacting galaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS, Sanders et al., Cat. <J/AJ/126/1607>), a complete sample of all galaxies having a 60{mu}m flux density greater than 5.24Jy. These systems were selected to have at least two distinguishable galaxies separated by less than three average galactic diameters, and thus we have excluded very widely separated systems and very advanced mergers. Additionally, some systems have been included that are more than three galactic diameters apart, yet have separations less than 4 and are thus likely to suffer from confusion in the RBGS. The new complete survey has the same properties as the prototype survey of Surace et al., 1993AJ....105..864S.
