- ID:
- ivo://CDS.VizieR/J/ApJ/799/205
- Title:
- [OII] emitting galaxies in the HETDEX survey
- Short Name:
- J/ApJ/799/205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) pilot survey identified 284 [OII]{lambda}3727 emitting galaxies in a 169arcmin^2^ field of sky in the redshift range 0<z<0.57. This line flux limited sample provides a bridge between studies in the local universe and higher-redshift [OII] surveys. We present an analysis of the star formation rates (SFRs) of these galaxies as a function of stellar mass as determined via spectral energy distribution fitting. The [OII] emitters fall on the "main sequence" of star-forming galaxies with SFR decreasing at lower masses and redshifts. However, the slope of our relation is flatter than that found for most other samples, a result of the metallicity dependence of the [OII] star formation rate indicator. The mass-specific SFR is higher for lower mass objects, supporting the idea that massive galaxies formed more quickly and efficiently than their lower mass counterparts. This is confirmed by the fact that the equivalent widths of the [OII] emission lines trend smaller with larger stellar mass. Examination of the morphologies of the [OII] emitters reveals that their star formation is not a result of mergers, and the galaxies' half-light radii do not indicate evolution of physical sizes.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/95/1629
- Title:
- [O III] emission in 2 field-galaxy surveys
- Short Name:
- J/AJ/95/1629
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present emission-line strengths for 394 galaxies from the field-galaxy redshift surveys of Kirshner, Oemler, and Schechter (1978, Cat. <J/AJ/83/1549>, KOS) and Kirshner et al. (1983, Cat. <J/AJ/88/1285>, KOSS) as part of a study of the nature of field and void galaxies. These data are 95% complete in their coverage of the [O III]{lambda}{lambda}5007,4959 emission lines. We find that 8.8%+/-1.5% of a J magnitude-limited data set have [O III]{lambda}5007 emission equivalent widths greater than 10A. There is no evidence that the spatial distribution of emission-line galaxies in each field differs from that of galaxies without emission. However, there is a significant increase in the fraction of galaxies with strong [O III] emission in the southern fields of the Kirshner, Oemler, and Schechter (1978, Cat. <J/J/83/1549>) survey as compared with the other survey fields. Our results are consistent with the conclusion that the fraction of galaxies with emission is larger in the Bootes void than in the general field, but tighter constraints on the void normal galaxy population are needed to improve the statistics.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A88
- Title:
- [OIII] of radio-emitting narrow-line Seyfert 1
- Short Name:
- J/A+A/591/A88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The [OIII] {lambda}{lambda} 4959, 5007 lines are a useful proxy to test the kinematic of the narrow-line region (NLR) in active galactic nuclei (AGN). In AGN, and particularly in narrow-line Seyfert 1 galaxies (NLS1s) these lines often show few peculiar features, such as blue wings, often interpreted as outflowing component, and a shift - typically toward lower wavelengths - of the whole spectroscopic feature in some exceptional sources, the so-called blue outliers, which are often associated to strong winds. We investigated the incidence of these peculiarities in two samples of radio-emitting NLS1s, one radio-loud and one radio-quiet. We also studied a few correlations between the observational properties of the [OIII] lines and those of the AGN. Our aim was to understand the difference between radio-quiet and radio-loud NLS1s, which may in turn provide useful information on the jet formation mechanism. We find that the NLR gas is much more perturbed in radio-loud than in radio-quiet NLS1s. In particular the NLR dynamics in {gamma}-ray emitting NLS1s appears to be highly disturbed, and this might be a consequence of interaction with the relativistic jet. The less frequently perturbed NLR in radio-quiet NLS1s suggests instead that these sources likely do not harbor a fully developed relativistic jet. Nonetheless blue-outliers in radio-quiet NLS1s are observed, and we interpret them as a product of strong winds.
- ID:
- ivo://CDS.VizieR/J/A+A/575/A40
- Title:
- [OII] luminosity function
- Short Name:
- J/A+A/575/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the [OII] luminosity function measured in the redshift range 0.1<z<1.65 with unprecedented depth and accuracy. Our measurements are based on medium resolution flux-calibrated spectra of emission line galaxies with the FORS2 instrument at VLT and with the SDSS-III/BOSS spectrograph. The FORS2 spectra and the corresponding catalog containing redshifts and line fluxes are released along with this paper. In this work we use a novel method to combine the aforementioned surveys with GAMA, zCOSMOS and VVDS, which have different target selection, producing a consistent weighting scheme to derive the [OII] luminosity function. The measured luminosity function is in good agreement with previous independent estimates. The comparison with two state-of-the-art semi-analytical models is good, which is encouraging for the production of mock catalogs of [OII] flux limited surveys. We observe the bright end evolution over 8.5Gyr: we measure the decrease of logL* from 42.4erg/s at redshift 1.44 to 41.2 at redshift 0.165 and we find that the faint end slope flattens when redshift decreases. This measurement confirms the feasibility of the target selection of future baryonic acoustic oscillation surveys aiming at observing [OII] flux limited samples.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/1910
- Title:
- [OII] nebular emission from MgII absorbers
- Short Name:
- J/MNRAS/471/1910
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present nebular emission associated with 198 strong Mg II absorbers at 0.35<=z<=1.1 in the fibre spectra of quasars from the Sloan Digital Sky Survey. Measured [OII] luminosities (L_[OII]_) are typical of sub-L* galaxies with derived star formation rate (uncorrected for fibre losses and dust reddening) in the range of 0.5-20M_{sun}_/yr. Typically less than ~3 per cent of the MgII systems with rest equivalent width, W_2796_>=2{AA}, show L_[OII]_>=0.3L*_[OII]_. The detection rate is found to increase with increasing W_2796_ and z. No significant correlation is found between W_2796_ and L_[OII]_ even when we restrict the samples to narrow z ranges. A strong correlation is seen between L_[OII]_ and z. While this is expected from the luminosity evolution of galaxies, we show that finite fibre size plays a very crucial role in this correlation. The measured nebular line ratios (like [OIII]/[OII] and [OIII]/H {beta}) and their z evolution are consistent with those of galaxies detected in deep surveys. Based on the median stacked spectra, we infer the average metallicity (logZ~8.3), ionization parameter (logq~7.5) and stellar mass (log (M/M_{sun}_)~9.3). The MgII systems with nebular emission typically have W_2796_>=2{AA}, MgII doublet ratio close to 1 and W(FeII{lambda}2600)/W_2796_~0.5 as often seen in damped Ly {alpha} and 21-cm absorbers at these redshifts. This is the biggest reported sample of [OII] emission from MgII absorbers at low-impact parameters ideally suited for probing various feedback processes at play in z<=1 galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1858
- Title:
- Old globular clusters in dwarf irregular galaxies
- Short Name:
- J/AJ/135/1858
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed a search for old globular clusters (GCs) using archival F606W and F814W Hubble Space Telescope/Advanced Camera for Surveys images of 19 Magellanic-type dwarf Irregular (dIrr) galaxies. Those dIrrs reside in nearby (2-8Mpc) associations of dwarf galaxies only. All dIrrs have absolute magnitudes fainter than or equal to that of the SMC (M_V_=-16.2mag). We detect in total 50 GC candidates in 13 dIrrs, of which 37 have (V-I) colors consistent with "blue" (old, metal-poor) GCs (bGCs). The luminosity function (LF) of the bGC candidates in our sample shows a turnover magnitude of M_V_=-7.41+/-0.22mag, consistent with other galaxy types.
- ID:
- ivo://CDS.VizieR/J/ApJ/634/861
- Title:
- Old passively evolving galaxies at z=1
- Short Name:
- J/ApJ/634/861
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained the number counts and the rest-frame B-band luminosity function of color-selected old passively evolving galaxies (OPEGs) at z=1 with very high statistical accuracy using a large and homogeneous sample of about 4000 such objects with z'<25 detected in an area of 1.03deg^2^ in the Subaru/XMM-Newton Deep Survey (SXDS) field. Our selection criteria are defined on the i'-z' and R-z' color-magnitude plane so that OPEGs at z=0.9-1.1 with formation redshift z_f_=2-10 are properly sampled with minimum contamination by other populations. The limiting magnitude corresponds to the luminosity of galaxies with M*+3 at z=0 (where M* is the characteristic absolute magnitude of the Schechter galaxy luminosity function). We made pilot redshift observations for 99 OPEG candidates with 19<z'<22 and found that at least 78% (73 of 93) of the entire sample, or 95% (73 of 77) of those whose redshifts were obtained, indeed lie between z=0.87 and 1.12, and most of their spectra show a continuum break and strong Ca H and K lines, indicating that these objects are indeed dominated by the old stellar populations.
- ID:
- ivo://CDS.VizieR/J/ApJ/805/160
- Title:
- Old star clusters in M101 from HST
- Short Name:
- J/ApJ/805/160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new photometric catalog of 326 candidate globular clusters (GCs) in the nearby spiral galaxy M101, selected from B, V, and I Hubble Space Telescope Advanced Camera for Surveys images. The luminosity function (LF) of these clusters has an unusually large number of faint sources compared with GCLFs in many other spiral galaxies. Accordingly, we separate and compare the properties of "bright" (M_v_<-6.5) versus "faint" (M_v_>-6.5; one magnitude fainter than the expected GC peak) clusters within our sample. The LF of the bright clusters is well fit by a peaked distribution similar to those observed in the Milky Way (MW) and other galaxies. These bright clusters also have similar size (r_eff_) and spatial distributions as MW GCs. The LF of the faint clusters, on the other hand, is well described by a power law, dN(L_v_)/dL_v_{propto}L_v_^{alpha}^ with {alpha}=2.6+/-0.3, similar to those observed for young and intermediate-age cluster systems in star forming galaxies. We find that the faint clusters have larger typical r_eff_ than the bright clusters, and have a flatter surface density profile, being more evenly distributed, as we would expect for clusters associated with the disk. We use the shape of the LF and predictions for mass-loss driven by two-body relaxation to constrain the ages of the faint clusters. Our results are consistent with two populations of old star clusters in M101: a bright population of halo clusters and a fainter, possibly younger, population of old disk clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/143/52
- Title:
- Old star clusters in NGC 4449 from HST imaging
- Short Name:
- J/AJ/143/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Hubble Space Telescope imaging to show that the nearby dwarf starburst galaxy NGC 4449 (=UGC 7592) has an unusual abundance of luminous red star clusters. Joint constraints from integrated photometry, low-resolution spectroscopy, dynamical mass-to-light ratios, and resolved color-magnitude diagrams provide evidence that some of these clusters are old globular clusters (GCs). Spectroscopic data for two massive clusters suggest intermediate metallicities ([Fe/H]~-1) and subsolar Mg enhancement ([Mg/Fe]~-0.1 to -0.2). One of these clusters may be the nucleus of a tidally disrupting dwarf galaxy; the other is very massive (~3*10^6^M_{sun}_). We have also identified a population of remote halo GCs. NGC 4449 is consistent with an emerging picture of the ubiquity of stellar halos among dwarf galaxies, and study of its GCs may help distinguish between accretion and in situ scenarios for such halos.
- ID:
- ivo://CDS.VizieR/J/ApJS/116/1
- Title:
- Old Stellar Populations. VI. Absorption-Line
- Short Name:
- J/ApJS/116/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present absorption-line strengths on the Lick/IDS line-strength system of 381 galaxies and 38 globular clusters in the 4000--6400 angstrom region. All galaxies were observed at Lick Observatory between 1972 and 1984 with the Cassegrain Image Dissector Scanner spectrograph, making this study one of the largest homogeneous collections of galaxy spectral line data to date. We also present a catalogue of nuclear velocity dispersions used to correct the absorption-line strengths onto the stellar Lick/IDS system. Extensive discussion of both random and systematic errors of the Lick/IDS system is provided. Indices are seen to fall into three families: alpha-element-like indices (including CN, Mg, Na D, and TiO2) that correlate positively with velocity dispersion; Fe-like indices (including Ca, the G band, TiO1, and all Fe indices) that correlate only weakly with velocity dispersion and the alpha indices; and Hbeta which anti-correlates with both velocity dispersion and the alpha indices. C2 4668 seems to be intermediate between the alpha and Fe groups. These groupings probably represent different element abundance families with different nucleosynthesis histories.
