- ID:
- ivo://CDS.VizieR/J/A+A/632/L7
- Title:
- High-redshift molecular outflow
- Short Name:
- J/A+A/632/L7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a high-redshift, massive molecular outflow in the starburst galaxy SPT 0346-52 (z=5.656) via the detected absorption of high-excitation water transitions (H_2_O 4_2,3_-4_1,4_ and H_2_O 3_3,0_-3_2,1_) with the Atacama Large Millimeter/submillimeter Array (ALMA). The host galaxy is one of the most powerful starburst galaxies at high redshift (star formation rate; SFR~3600M_{sun}_/yr), with an extremely compact (~320pc) star formation region and a SFR surface density ({SIGMA}_SFR_~5500M_{sun}_/yr/kpc^2^) five times higher than "maximum" (i.e. Eddington-limited) starbursts, implying a highly transient phase. The estimated outflow rate is ~500M_{sun}_/yr, which is much lower than the SFR, implying that in this extreme starburst the outflow capabilities saturate and the outflow is no longer capable of regulating star formation, resulting in a runaway process in which star formation will use up all available gas in less than 30Myr. Finally, while previous kinematic investigations of this source revealed possible evidence for an ongoing major merger, the coincidence of the hyper-compact starburst and high-excitation water absorption indicates that this is a single starburst galaxy surrounded by a disc.
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Search Results
- ID:
- ivo://CDS.VizieR/VII/182
- Title:
- High-Redshift Quasars (z>=2.2) in SGP and F401
- Short Name:
- VII/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Paper I) We provide details of a multicolor ( u, b_j_, v, or, r, i), wide-field, faint magnitude survey for high-redshift (z >= 2.2 ) quasars. The survey extends over the magnitude range 16<=m_or_<=20 and covers a total area of 58.6 square degrees. Sources of incompleteness in the photometric catalog are quantified, giving the survey an effective area of 45.7 square degrees. Particular attention is paid to the details of the plate-matching and image-classification procedures used in the generation of the photometric catalog from which quasars are selected, in order that the number of spurious quasar candidates be kept to an absolute minimum. The selection of candidates incorporates a number of novel features, including treating the multicolor information as low-resolution spectra, adopting a quantitative candidate identification algorithm that employs all the available information, and requiring only that objects be detected in the or passband. We describe how model quasar spectra are used to calculate the selection function for the survey, and we present the computed sample completeness, as a function of redshift and magnitude, for a range of representative quasar types. The spectroscopic results of the survey are reported in a companion paper and the derivation of the quasar luminosity function at high redshift will be reported in a third paper. (Paper II; see also documentation files "doc.tex" or "doc.txt") In a wide-field multicolor survey (45.7 deg^2^, 16.0<=m_or_<=20.0) we have discovered 130 new quasars, of which 100 are of redshift z>=2.2. There are 49 new quasars of redshift z>=3.0 including three of z>=4.0. We provide spectra, coordinates, redshifts, broad-band magnitudes (u, b_j_, v, or, r, i), line-equivalent widths for Lyman-{alpha}/NV and CIV, FWHM CIV, and continuum spectral indices for all the new quasars. The sample includes 96 quasars selected according to the rigid criteria detailed in the companion paper by Warren, Hewett, Irwin, and Osmer. These are combined with 14 previously known quasars in one of our fields, which also meet these selection criteria, to form a complete sample. The median equivalent width for Lyman-{alpha}/NV for the complete sample is 67A, and for CIV is 31{AA}. The median FWHM CIV is 35{AA} and the median spectral index is {alpha}=-0.60. The complete sample contains at least five broad absorption-line quasars. We have obtained spectra of a total of 473 multicolor selected candidates. The proportion of quasars found, including previously known quasars, of all redshifts, is 30%. The proportion of quasars of redshift z>=2.2 in the list of candidates that satisfy the selection criteria of the complete sample is 43%. Finally we limit the sample to the 85 objects of redshift z>=2.2 in the complete sample, and summarize the relevant observational data input to the calculation of the luminosity function, comprising the redshift versus magnitude distribution and the distribution of the spectral properties. The analysis of the luminosity function will be presented in a forthcoming paper.
- ID:
- ivo://CDS.VizieR/J/A+A/362/519
- Title:
- High redshift radio galaxies emission lines
- Short Name:
- J/A+A/362/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table gives radio and spectroscopic data for 167 radio galaxies, taken from the references given in the last column, from the WENSS, Texas and NVSS radio surveys, or determined from the electronic versions of the spectra.
- 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/AJ/141/23
- Title:
- HI holes in THINGS galaxies
- Short Name:
- J/AJ/141/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the properties of HI holes detected in 20 galaxies that are part of "The HI Nearby Galaxy Survey." We detected more than 1000 holes in total in the sampled galaxies. Where they can be measured, their sizes range from about 100pc (our resolution limit) to about 2kpc, their expansion velocities range from 4 to 36km/s, and their ages are estimated to range between 3 and 150Myr. The holes are found throughout the disks of the galaxies, out to the edge of the HI disk; 23% of the holes fall outside R25. We find that shear limits the age of holes in spirals (shear is less important in dwarf galaxies) which explains why HI holes in dwarfs are rounder, on average than in spirals.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A23
- Title:
- HII-chi-mistry-IR. Abundances
- Short Name:
- J/A+A/652/A23
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We provide a new method to derive heavy element abundances based on the unique suite of nebular lines in the mid- to far-infrared (IR) range. Using grids of photo-ionisation models that cover a wide range in O/H and N/O abundances, and ionisation parameter, our code HII-CHI-MISTRY-IR (HCm-IR) provides model-based abundances based on extinction free and temperature insensitive tracers, two significant advantages over optical diagnostics. The code is probed using a sample of 56 galaxies observed with Spitzer and Herschel covering a wide range in metallicity, 7.2~<12+log(O/H)~<8.9. The IR model-based metallicities obtained are robust within a scatter of 0.03dex when the hydrogen recombination lines, which are typically faint transitions in the IR range, are not available. When compared to the optical abundances obtained with the direct method,model- based methods, and strong-line calibrations, HCm-IR estimates show a typical dispersion of ~0.2dex, in line with previous studies comparing IR and optical abundances, a do not introduce a noticeable systematic above 12+log(O/H)>7.6. This accuracy can be achieved using the lines [SIV]10.5um, [SIII]18.7,33.5um, [NeIII]15.6um and [NeII]12.8um. Additionally, HCm-IR provides an independent N/O measurement when the [OIII]52,88um and [NIII]57um transitions are measured, and therefore the derived abundances in this case do not rely on particular assumptions in the N/O ratio. Large uncertainties (~0.4dex) may affect the abundance determinations of galaxies at sub- or over-solar metallicities when a solar-like N/O ratio is adopted. Finally, the code has been applied to 8 galaxies located at 1.8<z<7.5 with ground-based detections of far-IR lines redshifted in the submm range, revealing solar-like N/O and O/H abundances in agreement with recent studies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/757
- Title:
- HII complexes optical and IR emissions
- Short Name:
- J/MNRAS/444/757
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of optical spectroscopy and infrared aperture photometry of more than 100 HII complexes in nine galaxies. Spectra obtained with the 6-m telescope of Special Astrophysical Observatory of the Russian Academy of Sciences are used along with archival data from Spitzer and several ground-based telescopes to infer a strength of polycyclic aromatic hydrocarbon (PAH) emission, age, properties of the UV radiation field, and metallicity of studied HII complexes. Physical properties (age, radiation field parameters, metallicity) are related to the F_8_/F_24_ ratio used as a proxy for the PAH abundance in order to reveal factors that may influence the PAH evolution in HII complexes. The well-known correlation between the F_8_/F_24_ ratio and metallicity is confirmed in the studied complexes. The infrared flux ratio also correlates with the [Oiii]{lambda}5007/H{beta} ratio which is often considered as an indicator of the radiation field hardness, but this correlation seems to be a mere reflection of a correlation between [Oiii]{lambda}5007/H{beta} and metallicity. In separate metallicity bins, the F_8_/F_24_ ratio is found to correlate with an age of an Hii complex, which is estimated from the equivalent width of H{beta} line. The correlation is positive for low-metallicity complexes and negative for high-metallicity complexes. Analysing various mechanisms of PAH formation and destruction in the context of found correlations, we suggest that PAH abundance is likely altered by the UV radiation within HII complexes, but this is not necessarily due to their destruction. If PAHs can also form in Hii complexes due to some processes like aromatization, photodestruction, shattering and sputtering of very small grains, the net F_8_/F_24_ ratio is determined by a balance between all these processes that can be different at different metallicities.
- ID:
- ivo://CDS.VizieR/J/A+A/476/89
- Title:
- HII galaxies narrow-band Hbeta images
- Short Name:
- J/A+A/476/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aims is to create a catalog of images of HII galaxies and their individual star-formation regions in order to study the distribution of the gas emission and their underlying stellar continuum. We have used H{beta} narrow-band images of 43 selected HII galaxies obtained at ESO NTT 3.58m telescope using the SUSI2 camera. Surface photometric H{beta} fluxes and equivalent widths for all objects and star-formation regions are presented in this catalog.
