- ID:
- ivo://CDS.VizieR/J/ApJ/735/71
- Title:
- Oxygen abundances in outlying HII regions
- Short Name:
- J/ApJ/735/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a search for outlying HII regions in the extended gaseous outskirts of nearby (D<40Mpc) galaxies and subsequent multi-slit spectroscopy used to obtain the HII region nebular oxygen abundances. The galaxies in our sample have extended HI disks and/or interaction-related HI features that extend well beyond their primary stellar components. We report oxygen abundance gradients out to 2.5 times the optical radius for these galaxies which span a range of morphologies and masses. We analyze the underlying stellar and neutral HI gas distributions in the vicinity of the HII regions to understand the physical processes that give rise to the observed metal distributions in galaxies. These measurements, for the first time, convincingly show flat abundance distributions out to large radii in a wide variety of systems and have broad implications for galaxy chemodynamical evolution.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/617/240
- Title:
- Oxygen abundances in the GOODS-North field
- Short Name:
- J/ApJ/617/240
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure nebular oxygen abundances for 204 emission-line galaxies with redshifts 0.3<z<1.0 in the Great Observatories Origins Deep Survey-North (GOODS-N) field using spectra from the Team Keck Redshift Survey, Cat. <J/AJ/127/3121>. We also provide an updated analytic prescription for estimating oxygen abundances using the traditional strong emission line ratio, R_23_, based on the photoionization models of Kewley & Dopita (2002ApJS..142...35K). We include an analytic formula for very crude metallicity estimates using the [NII]_{lambda}6584_/H{alpha} ratio.
- ID:
- ivo://CDS.VizieR/J/ApJ/674/172
- Title:
- Oxygen abundances of LIRGs and ULIRGs
- Short Name:
- J/ApJ/674/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) dominate the star formation rate budget of the universe at z>~1, yet no local measurements of their heavy-element abundances exist. We measure nuclear or near-nuclear oxygen abundances in a sample of 100 star-forming LIRGs and ULIRGs using new, previously published, and archival spectroscopy of strong emission lines (including [OII] {lambda}{lambda}3726, 3729) in galaxies with redshifts <z>~0.1.
2774. OzDES DR1
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/273
- Title:
- OzDES DR1
- Short Name:
- J/MNRAS/472/273
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results for the first three years of OzDES, a six-year program to obtain redshifts for objects in the Dark Energy Survey (DES) supernova fields using the 2dF fibre positioner and AAOmega spectrograph on the Anglo-Australian Telescope. OzDES is a multi-object spectroscopic survey targeting multiple types of targets at multiple epochs over a multi-year baseline, and is one of the first multi-object spectroscopic surveys to dynamically include transients into the target list soon after their discovery. At the end of three years, OzDES has spectroscopically confirmed almost 100 supernovae, and has measured redshifts for 17,000 objects, including the redshifts of 2,566 supernova hosts. We examine how our ability to measure redshifts for targets of various types depends on signal-to-noise, magnitude, and exposure time, finding that our redshift success rate increases significantly at a signal-to-noise of 2 to 3 per 1-Angstrom bin. We also find that the change in signal-to-noise with exposure time closely matches the Poisson limit for stacked exposures as long as 10 hours. We use these results to predict the redshift yield of the full OzDES survey, as well as the potential yields of future surveys on other facilities such as 4MOST, PFS, and MSE. This work marks the first OzDES data release, comprising 14,693 redshifts. OzDES is on target to obtain over 30,000 redshifts over the six-year duration of the survey, including a yield of approximately 5,700 supernova host-galaxy redshifts.
- ID:
- ivo://CDS.VizieR/J/ApJ/772/27
- Title:
- Pa{alpha} (1.87um) LF of HII regions in 12 galaxies
- Short Name:
- J/ApJ/772/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The H II region luminosity function (LF) is an important tool for deriving the birthrates and mass distribution of OB associations and is an excellent tracer of the newly formed massive stars and associations. To date, extensive work (predominantly in H{alpha}) has been done from the ground, which is hindered by dust extinction and the severe blending of adjacent (spatially or in projection) H II regions. Reliably measuring the properties of H II regions requires a linear resolution <40pc, but analyses satisfying this requirement have been done only in a handful of galaxies, so far. As the first space-based work using a galaxy sample, we have selected 12 galaxies from our HST/NICMOS Pa{alpha} survey and studied the LF and size distribution of H II regions both in individual galaxies and cumulatively, using a virtually extinction-free tracer of the ionizing photon rate. The high angular resolution and low sensitivity to diffuse emission of NICMOS also offer an advantage over ground-based imaging by enabling a higher degree of de-blending of the H II regions. We do not confirm the broken power-law LFs found in ground-based studies. Instead, we find that the LFs, both individual and co-added, follow a single power law dN(L)/dlnL{propto}L^-1^, are consistent with the mass function of star clusters in nearby galaxies, and are in agreement with the results of the existing analyses with Hubble Space Telescope (HST) data. The individual and co-added size distributions of H II regions are both roughly consistent with dN(D)/dlnD{propto}D^-3^, but the power-law scaling is probably contaminated by blended regions or complexes.
- ID:
- ivo://CDS.VizieR/J/ApJ/892/23
- Title:
- Pa-beta, Ha and attenuation in NGC5194 & NGC6946
- Short Name:
- J/ApJ/892/23
- Date:
- 19 Jan 2022 08:58:18
- Publisher:
- CDS
- Description:
- We combine Hubble Space Telescope Paschen {beta} (Pa{beta}) imaging with ground-based, previously published H{alpha} maps to estimate the attenuation affecting H{alpha}, A(H{alpha}), across the nearby, face-on galaxies NGC 5194 and NGC 6946. We estimate A(H{alpha}) in ~2000 independent 2" ~75pc diameter apertures in each galaxy, spanning out to a galactocentric radius of almost 10kpc. In both galaxies, A(H{alpha}) drops with radius, with a bright, high-attenuation inner region, though in detail the profiles differ between the two galaxies. Regions with the highest attenuation-corrected H{alpha} luminosity show the highest attenuation, but the observed H{alpha} luminosity of a region is not a good predictor of attenuation in our data. Consistent with much previous work, the IR-to-H{alpha} color does a good job of predicting A(H{alpha}). We calculate the best-fit empirical coefficients for use combining H{alpha} with 8, 12, 24, 70, or 100{mu}m to correct for attenuation. These agree well with previous work, but we also measure significant scatter around each of these linear relations. The local atomic plus molecular gas column density, N(H), also predicts A(H{alpha}) well. We show that a screen with magnitude ~0.2 times that expected for a Milky Way gas-to-dust value does a reasonable job of explaining A(H{alpha}) as a function of N(H). This could be expected if only ~40% of gas and dust directly overlap regions of H{alpha} emission.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/1597
- Title:
- PACO catalogue of bright sources
- Short Name:
- J/MNRAS/415/1597
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Planck Australia Telescope Compact Array (Planck-ATCA) Co-eval Observations (PACO) have provided flux density measurements of well-defined samples of Australia Telescope 20GHz (AT20G) radio sources at frequencies below and overlapping with Planck frequency bands, almost simultaneously with Planck observations. We have observed with the ATCA a total of 482 sources in the frequency range between 4.5 and 40GHz in the period between 2009 July and 2010 August. Several sources were observed more than once. In this paper we present the aims of the project, the selection criteria, and the observation and data reduction procedures.
- ID:
- ivo://CDS.VizieR/J/MNRAS/416/559
- Title:
- PACO faint sources catalog
- Short Name:
- J/MNRAS/416/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Planck-ATCA Coeval Observations (PACO) project collected data between 4.5 and 40GHz for 482 sources selected within the Australia Telescope 20GHz (AT20G) catalogue and observed with the Australia Telescope Compact Array. Observations were done almost simultaneously with the Planck satellite, in the period between 2009 July and 2010 August. In this paper, we present and discuss the data for the complete sample of 159 sources with S_AT20G_>200mJy in the South Ecliptic Pole region.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/1845
- Title:
- PACO spectrally selected sample
- Short Name:
- J/MNRAS/428/1845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Planck Australia Telescope Compact Array (Planck-ATCA) Co-eval Observations (PACO) have provided multi-frequency (5-40GHz) flux density measurements of complete samples of Australia Telescope 20GHz (AT20G) radio sources at frequencies below and overlapping with Planck frequency bands, almost simultaneously with Planck observations. In this work we analyse the data in total intensity for the spectrally selected PACO sample, a complete sample of 69 sources brighter than S20GHz=200mJy selected from the AT20G survey catalogue to be inverted or upturning between 5 and 20GHz. We study the spectral behaviour and variability of the sample. We use the variability between AT20G (2004-2007) and PACO (2009-2010) epochs to discriminate between candidate High-Frequency Peakers (HFPs) and candidate blazars. The HFPs picked up by our selection criteria have spectral peaks >10GHz in the observer frame and turn out to be rare (<0.5% of the S20GHz>=200mJy sources), consistent with the short duration of this phase implied by the "youth" scenario. Most (=~89%) of blazar candidates have remarkably smooth spectra, well described by a double power law, suggesting that the emission in the PACO frequency range is dominated by a single emitting region. Sources with peaked PACO spectra show a decrease of the peak frequency with time at a mean rate of -3+/-2GHz/yr on an average time-scale of <{tau}>=2.1+/-0.5yr (median: {tau}median=1.3yr). The 5-20GHz spectral indices show a systematic decrease from AT20G to PACO. At higher frequencies spectral indices steepen: the median {alpha}4030 is steeper than the median {alpha}205 by {delta}{alpha}=0.6. Taking further into account the Wide-field Infrared Survey Explorer data we find that the Spectral Energy Distributions (SEDs), {nu}S({nu}), of most of our blazars peak at {nu}SEDp<105GHz; the median peak wavelength is {lambda}SEDp=~93{mu}m. Only six have {nu}SEDp>105GHz.
- ID:
- ivo://CDS.VizieR/J/A+A/532/A90
- Title:
- PACS Evolutionary Probe (PEP-DR1) catalogs
- Short Name:
- J/A+A/532/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep far-infrared photometric surveys studying galaxy evolution and the nature of the cosmic infrared background are a key strength of the Herschel mission. We describe the scientific motivation for the PACS Evolutionary Probe (PEP) guaranteed time key program and its role within the entire set of Herschel surveys, and the field selection that includes popular multiwavelength fields such as GOODS, COSMOS, Lockman Hole (LH), ECDFS (Extended Chandra Deep Field South), and EGS (Extended Groth Strip). We present results from the deepest Herschel-PACS (Photodetector Array Camera and Spectrometer) far-infrared blank field extragalactic survey, obtained by combining observations of the GOODS (Great Observatories Origins Deep Survey) fields from the PACS Evolutionary Probe (PEP) and GOODS-Herschel key programmes.
