- ID:
- ivo://CDS.VizieR/J/A+A/599/A83
- Title:
- ELG and AGN in WINGS clusters
- Short Name:
- J/A+A/599/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the emission line galaxies members of 46 low-redshift (0.04<z<0.07) clusters observed by WINGS (WIde-field Nearby Galaxy cluster Survey; Fasano et al., 2006A&A...445..805F). Emission line galaxies were identified following criteria that are meant to minimize biases against non-star-forming galaxies and classified employing diagnostic diagrams. We examined the emission line properties and frequencies of star-forming galaxies, transition objects, and active galactic nuclei (AGNs: LINERs and Seyferts), unclassified galaxies with emission lines, and quiescent galaxies with no detectable line emission. A deficit of emission line galaxies in the cluster environment is indicated by both a lower frequency, and a systematically lower Balmer emission line equivalent width and luminosity with respect to control samples; this implies a lower amount of ionized gas per unit mass and a lower star formation rate if the source is classified as Hii region. A sizable population of transition objects and of low-luminosity LINERs (~10-20% of all emission line galaxies) are detected among WINGS cluster galaxies. These sources are a factor of 1.5 more frequent, or at least as frequent, as in control samples with respect to Hii sources. Transition objects and LINERs in clusters are most affected in terms of line equivalent width by the environment and appear predominantly consistent with so-called retired galaxies. Shock heating can be a possible gas excitation mechanism that is able to account for observed line ratios. Specific to the cluster environment, we suggest interaction between atomic and molecular gas and the intracluster medium as a possible physical cause of line-emitting shocks.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/693/617
- Title:
- Ellipticities of cluster early-type galaxies
- Short Name:
- J/ApJ/693/617
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a sample of early-type cluster galaxies from 0<z<1.3 and measured the evolution of their ellipticity distributions. Our sample contains 487 galaxies in 17 z>0.3 clusters with high-quality space-based imaging and a comparable sample of 210 galaxies in 10 clusters at z<0.05. We select early-type galaxies (elliptical and S0 galaxies) that fall within the cluster R_200_, and which lie on the red-sequence in the magnitude range -19.3>M_B_>-21, after correcting for luminosity evolution as measured by the fundamental plane.
- ID:
- ivo://CDS.VizieR/J/MNRAS/365/454
- Title:
- Emission line analysis of HII galaxies
- Short Name:
- J/MNRAS/365/454
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a statistical study of a very large sample of HII galaxies taken from the literature. We focus on the differences in several properties between galaxies that show the auroral line [OIII]{lambda}4363 and those that do not present this feature in their spectra.
- ID:
- ivo://CDS.VizieR/J/ApJS/192/5
- Title:
- Emission-line galaxies from HETDEX pilot survey
- Short Name:
- J/ApJS/192/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of emission-line galaxies selected solely by their emission-line fluxes using a wide-field integral field spectrograph. This work is partially motivated as a pilot survey for the upcoming Hobby-Eberly Telescope Dark Energy Experiment. We describe the observations, reductions, detections, redshift classifications, line fluxes, and counterpart information for 397 emission-line galaxies detected over 169arcmin^2^ with a 3500-5800{AA} bandpass under 5{AA} full-width-half-maximum (FWHM) spectral resolution. The survey's best sensitivity for unresolved objects under photometric conditions is between 4 and 20x10^-17^erg/s/cm^2^ depending on the wavelength, and Ly{alpha} luminosities between 3x10^42^ and 6x10^42^erg/s are detectable. This survey method complements narrowband and color-selection techniques in the search of high-redshift galaxies with its different selection properties and large volume probed. The four survey fields within the COSMOS, GOODS-N, MUNICS, and XMM-LSS areas are rich with existing, complementary data. We find 105 galaxies via their high-redshift Ly{alpha} emission at 1.9<z<3.8, and the majority of the remainder objects are low-redshift [OII]3727 emitters at z<0.56. The classification between low- and high-redshift objects depends on rest-frame equivalent width (EW), as well as other indicators, where available. Based on matches to X-ray catalogs, the active galactic nuclei fraction among the Ly{alpha} emitters is 6%. We also analyze the survey's completeness and contamination properties through simulations. We find five high-z, highly significant, resolved objects with FWHM sizes >44arcmin^2^ which appear to be extended Ly{alpha} nebulae. We also find three high-z objects with rest-frame Ly{alpha} EW above the level believed to be achievable with normal star formation, EW0>240{AA}.
- ID:
- ivo://CDS.VizieR/J/AJ/138/1022
- Title:
- Emission-line galaxies from HST PEARS survey
- Short Name:
- J/AJ/138/1022
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a search for emission-line galaxies (ELGs) in the southern fields of the Hubble Space Telescope Probing Evolution And Reionization Spectroscopically (PEARS) grism survey. The PEARS South Fields consist of five Advanced Camera for Surveys pointings (including the Hubble Ultra Deep Field) with the G800L grism for a total of 120 orbits, revealing thousands of faint object spectra in the GOODS-South region of the sky. ELGs are one subset of objects that are prevalent among the grism spectra. Using a two-dimensional detection and extraction procedure, we find 320 emission lines originating from 226 galaxy "knots" within 192 individual galaxies. Line identification results in 118 new grism-spectroscopic redshifts for galaxies in the GOODS-South Field. We measure emission-line fluxes using standard Gaussian fitting techniques. The star formation rates of the ELGs are presented, as well as a sample of distinct giant star-forming regions at z~0.1-0.5 across individual galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/772/48
- Title:
- Emission-line galaxies from PEARS. II.
- Short Name:
- J/ApJ/772/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitess grism spectroscopic data obtained with the Advanced Camera for Surveys on board Hubble Space Telescope. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random survey of galaxies, as well as the availability of a wide variety of ancillary observations complemented by the spectroscopic results. Using the PEARS data, we are able to identify star-forming galaxies (SFGs) within the redshift volume 0<z<1.5. Star-forming regions in the PEARS survey are pinpointed independently of the host galaxy. This method allows us to detect the presence of multiple emission-line regions (ELRs) within a single galaxy. We identified a total of 1162 H{alpha}, [OIII], and/or [OII] emission lines in the PEARS sample of 906 galaxies to a limiting flux of ~10^-18^erg/s/cm2. The ELRs have also been compared to the properties of the host galaxy, including morphology, luminosity, and mass. From this analysis, we find three key results: (1) the computed line luminosities show evidence of a flattening in the luminosity function with increasing redshift; (2) the star-forming systems show evidence of complex morphologies with star formation occurring predominantly within one effective (half-light) radius. However, the morphologies show no correlation with host stellar mass. (3) Also, the number density of SFGs with M_*_>=10^9^M_{sun}_ decreases by an order of magnitude at z<=0.5 relative to the number at 0.5<z<0.9, supporting the argument of galaxy downsizing.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/1043
- Title:
- Emission-line galaxies from SDSS DR7
- Short Name:
- J/MNRAS/421/1043
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 2865 emission-line galaxies with strong nebular HeII{lambda}4686 emissions in the Sloan Digital Sky Survey Data Release 7 and use this sample to investigate the origin of this line in star-forming galaxies. We show that star-forming galaxies and galaxies dominated by an active galactic nucleus form clearly separated branches in the HeII{lambda}4686/H{beta} versus [NII]{lambda}6584/H{alpha} diagnostic diagram and derive an empirical classification scheme which separates the two classes. We also present an analysis of the physical properties of 189 star-forming galaxies with strong HeII{lambda}4686 emissions. These star-forming galaxies provide constraints on the hard ionizing continuum of massive stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/201/31
- Title:
- Emission-line galaxies from SDSS. I.
- Short Name:
- J/ApJS/201/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recently, much attention has been paid to double-peaked narrow emission-line (NEL) galaxies, some of which are suggested to be related to merging galaxies. We make a systematic search to build the largest sample of these sources from Data Release 7 of the Sloan Digital Sky Survey (SDSS). With reasonable criteria for fluxes, FWHMs of the emission lines, and separations of the peaks, we select 3030 double-peaked NEL galaxies. In light of the existence of broad Balmer lines and the locations of the two components of double-peaked NELs distinguished by the Kauffmann et al. (2003MNRAS.346.1055K) criteria in the Baldwin-Phillips-Terlevich diagram, we find that there are 81 Type I active galactic nuclei (AGNs), 837 double Type II AGNs (2-Type II), 708 galaxies with double star-forming components (2-SF), 400 with mixed star-forming and Type II AGN components (Type II + SF), and 1004 unknown-type objects. As a by-product, a sample of galaxies (12582) with asymmetric or top-flat profiles of emission lines is established. After visually inspecting the SDSS images of the two samples, we find 54 galaxies with dual cores.
- ID:
- ivo://CDS.VizieR/J/ApJ/888/79
- Title:
- Emission-line galaxies from the FIGS survey
- Short Name:
- J/ApJ/888/79
- Date:
- 25 Oct 2021 10:14:43
- Publisher:
- CDS
- Description:
- We present a catalog of 208 0.3<z<2.1 emission-line galaxies (ELGs) selected from 1D slitless spectroscopy obtained using Hubble's WFC3 G102 grism, as part of the Faint Infrared Grism Survey. We identify ELG candidates by searching for significant peaks in all continuum-subtracted G102 spectra and, where possible, confirm candidates by identifying consistent emission lines in other available spectra or with published spectroscopic redshifts. We provide derived emission-line fluxes and errors, redshifts, and equivalent widths for H{alpha}{lambda}6563, [OIII]{lambda}{lambda}4959,5007, and [OII]{lambda}3727 emission lines, for ELGs down to AB(F105W)>28 and >10^-17^erg/cm^2^/s line flux. We use the resulting line catalog to investigate a possible relationship between line emission and a galaxy's environment. We use seventh-nearest-neighbor distances to investigate the typical surroundings of ELGs compared to non-ELGs, and we find that [OIII] emitters are preferentially found at intermediate galaxy densities near galaxy groups. We characterize these ELGs in terms of the galaxy specific star formation rate (SFR) versus stellar mass and find no significant influence of environment on that relation. We calculate SFRs and find no dependence of SFR on local galaxy surface density for 0.3<z<0.8 H{alpha} emitters and for 0.8<z<1.3 [OIII] emitters. We find similar rates of close-pair interaction between ELGs and non-ELGs. For galaxy surface densities {Sigma}<=30Mpc^-2^, we find no consistent effect of environment on star formation.
- ID:
- ivo://CDS.VizieR/J/A+AS/116/43
- Title:
- Emission-line galaxies nearby voids.
- Short Name:
- J/A+AS/116/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the observational results of our search for emission-line galaxies (ELG) towards nearby voids. In order to find ELG, we started a survey using the IIIa-J objective prism plates from the Hamburg QSO Survey. The plates are digitized and an automatic procedure was applied to select the candidates. Digitized direct plates were used to determine coordinates and to reject overlaps between spectra. The accuracy of the coordinates is +/-2". A total area of 1248deg^2^ was scanned, distributed in four different regions. All the selected objects were observed with follow-up spectroscopy. We have obtained a final sample of 203 objects, of which 196 are emission-line galaxies, four are galaxies with absorption lines and three are QSOs. Almost half of our objects are newly discovered ones and three quarters of the given redshifts are new. Our sample contains mainly high ionization galaxies and is less sensitive in the detection of low-ionization objects. The apparent magnitudes, as derived from the objective prism plates, range between 15.0<=B<=19.5. The sample is dominated by nearby galaxies, with a peak in the redshift distribution at cz=4500 km/s.