- ID:
- ivo://CDS.VizieR/J/MNRAS/337/256
- Title:
- Galaxy in low X-ray luminosity clusters
- Short Name:
- J/MNRAS/337/256
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first spectroscopic survey of intrinsically low X-ray luminosity clusters at z>>0, with Hubble Space Telescope (HST) WFPC2 imaging and spectroscopy from Calar Alto and WHT-LDSS2. We study 172 confirmed cluster members in a sample of ten clusters at 0.23<z<0.3, with LX<~4x10^43^h^-2^erg/s[0.1-2.4keV]. The core of each cluster is imaged with WFPC2 in the F702W filter, and the spectroscopic sample is statistically complete to Mr~-19.0+5logh, within an 11' (~1.8h^-1^Mpc) field. The clusters are dynamically well-separated from the surrounding field and most have velocity distributions consistent with Gaussians. The velocity dispersions range from 350-850km/s, consistent with the local L_X_-{sigma} correlation. All 10 clusters host a bright, giant elliptical galaxy without emission lines, near the centre of the X-ray emission. We measure the equivalent width of two nebular emission lines, [O II] and H{alpha}, and the H{delta} absorption line to classify the cluster members spectrally. Galaxy morphologies are measured from the HST images, using the two-dimensional surface-brightness fitting software GIM2D.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/527/A101
- Title:
- Galaxy population of Abell 1367
- Short Name:
- J/A+A/527/A101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic and photometric data of the galaxy population of the galaxy cluster Abell 1367, over a field of 34'x90', covering the cluster centre out to a radius of ~2.2Mpc, are presented as the first stage of a study of their stellar population and star formation properties. Spectroscopic catalogue contains new detection data of emission and/or absorption lines for 84 galaxies in our survey regions. Photometric data give optical and near-infrared isophotal magnitudes for 303 galaxies, determined within R_24_ isophotal diameters. H{alpha} emission catalogue reports equivalent widths and fluxes of 72 galaxies, confirmed as cluster members of Abell 1367.
- ID:
- ivo://CDS.VizieR/J/PASP/125/477
- Title:
- Gas Survey of Protoplanetary Systems. I.
- Short Name:
- J/PASP/125/477
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a large-scale far-infrared line and continuum survey of protoplanetary disk through to young debris disk systems carried out using the ACS instrument on the Herschel Space Observatory. This Open Time Key program, known as GASPS (Gas Survey of Protoplanetary Systems), targeted ~250 young stars in narrow wavelength regions covering the [OI] fine structure line at 63um the brightest far-infrared line in such objects. A subset of the brightest targets were also surveyed in [OI]145um, [CII] at 157um, as well as several transitions of HO and high-excitation CO lines at selected wavelengths between 78 and 180um. Additionally, GASPS included continuum photometry at 70, 100 and 160um, around the peak of the dust emission.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/2679
- Title:
- GEEC2 spectroscopic survey of Galaxy groups
- Short Name:
- J/MNRAS/443/2679
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the data release of the Gemini-South GMOS spectroscopy in the fields of 11 galaxy groups at 0.8<z<1, within the COSMOS field. This forms the basis of the Galaxy Environment Evolution Collaboration 2 (GEEC2) project to study galaxy evolution in haloes with M~10^13^M_{sun}_ across cosmic time. The final sample includes 162 spectroscopically confirmed members with R<24.75, and is >50% complete for galaxies within the virial radius, and with stellar mass M_star_>10^10.3^M_{sun}_. Including galaxies with photometric redshifts, we have an effective sample size of ~400 galaxies within the virial radii of these groups. We present group velocity dispersions, dynamical and stellar masses. Combining with the GCLASS sample of more massive clusters at the same redshift, we find the total stellar mass is strongly correlated with the dynamical mass, with logM_200_=1.20(logM_star_-12)+14.07. This stellar fraction of ~1% is lower than predicted by some halo occupation distribution models, though the weak dependence on halo mass is in good agreement. Most groups have an easily identifiable most massive galaxy (MMG) near the centre of the galaxy distribution, and we present the spectroscopic properties and surface brightness fits to these galaxies. The total stellar mass distribution in the groups, excluding the MMG, compares well with an NFW (Navarro Frenk & White) profile with concentration 4, for galaxies beyond ~0.2R_200_. This is more concentrated than the number density distribution, demonstrating that there is some mass segregation.
- ID:
- ivo://CDS.VizieR/J/ApJ/873/35
- Title:
- Gemini GNIRS NIR spectroscopy of 50 QSOs at z>~5.7
- Short Name:
- J/ApJ/873/35
- Date:
- 19 Jan 2022 09:09:09
- Publisher:
- CDS
- Description:
- We report initial results from a large Gemini program to observe z>~5.7 quasars with GNIRS near-IR spectroscopy. Our sample includes 50 quasars with simultaneous ~0.85-2.5{mu}m spectra covering the rest-frame ultraviolet and major broad emission lines from Ly{alpha} to MgII. We present spectral measurements for these quasars and compare with their lower redshift counterparts at z=1.5-2.3. We find that when quasar luminosity is matched, there are no significant differences between the rest-UV spectra of z>~5.7 quasars and the low-z comparison sample. High-z quasars have similar continuum and emission line properties and occupy the same region in the black hole mass and luminosity space as the comparison sample, accreting at an average Eddington ratio of ~0.3. There is no evidence for super-Eddington accretion or hypermassive (>10^10^M_{sun}_) black holes within our sample. We find a mild excess of quasars with weak CIV lines relative to the control sample. Our results, corroborating earlier studies but with better statistics, demonstrate that these high-z quasars are already mature systems of accreting supermassive black holes operating with the same physical mechanisms as those at lower redshifts.
- ID:
- ivo://CDS.VizieR/J/A+A/603/L7
- Title:
- 6 giants atomic data and equivalent widths
- Short Name:
- J/A+A/603/L7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed six He-clump stars of the intermediate-age stellar cluster Gaia1 with the MIKE/MAGELLAN spectrograph. A possible extra-galactic origin of this cluster, recently discovered thanks to the first data release of the ESA Gaia mission, has been suggested, based on its orbital parameters. Abundances for Fe, {alpha}, proton- and neutron-capture elements have been obtained. We find no evidence of intrinsic abundance spreads. The iron abundance is solar ([FeI/H]=+0.00+/-0.01; {sigma}=0.03dex). All the other abundance ratios are generally solar-scaled, similar to the Galactic thin disk and open cluster stars of similar metallicity. The chemical composition of Gaia1 does not support an extra-galactic origin for this stellar cluster, which can be considered as a standard Galactic open cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A14
- Title:
- GIBS sources equivalent widths
- Short Name:
- J/A+A/645/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We developed a set of procedures to automatically detect and measure the DIB around 8620{AA} (the Gaia DIB) for a wide range of temperatures. The method was tested on about 5000 spectra from the Giraffe Inner Bulge Survey (GIBS; Zoccali et al., 2014A&A...562A..66Z), and 4194 reasonable fitting results were got. We made use of the reddenings, E(J-Ks), from the extinction map developed by Surot et al. (2020arXiv201002723S). A linear correlation between the equivalent width (EW) and E(J-Ks) was derived as E(J-Ks)/EW = 1.875, according to E(B-V)/EW = 2.721, which is highly consistent with previous results toward similar sightlines. After a correction based on the Vista Variables in the Via Lactea (VVV; Minniti et al., 2010NewA...15..433M) database for both EW and E(J-Ks), the coefficient derived from individual GIBS fields, E(J-Ks)/EW=1.884, is also in perfect agreement with literature values. Based on a subsample of 1015 stars toward the Galactic center, we determined a rest-frame wavelength of the Gaia DIB as 8620.55{AA}. A Gaussian profile is proved to be a proper and stable assumption for the Gaia DIB as no intrinsic asymmetry is found.
- ID:
- ivo://CDS.VizieR/J/ApJ/901/23
- Title:
- Gjoll stream stars & detailed abund. of 4 members
- Short Name:
- J/ApJ/901/23
- Date:
- 15 Feb 2022 14:07:06
- Publisher:
- CDS
- Description:
- Recent analysis of the second data release of Gaia has revealed a number of new stellar streams surrounding the Milky Way. It has been suggested that one of these streams, Gjoll, is associated with the globular cluster NGC 3201, but thus far the association has only been based on kinematics of the stream stars. In this work we identify five likely stream members in the Gaia data that are bright enough for high-resolution spectroscopic follow-up with the Harlan J. Smith telescope at McDonald Observatory. One star is ruled out as a member based on its radial velocity. Abundance analysis of the remaining four kinematic members reveals a good chemical match to NGC 3201 for two of the stars, driven by their similar Al and {alpha}-element abundances. Of the remaining two, one shows no chemical similarity to NGC 3201 and is likely an unassociated Milky Way halo field star, while the other exhibits a similar Al abundance but has somewhat lower {alpha}-element abundances. The chemical tagging of stars in the Gjoll stream to NGC3201 confirms this association and provides direct proof of the hierarchical formation of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/178
- Title:
- GLASS. VII. H{alpha} maps
- Short Name:
- J/ApJ/833/178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exploiting the slitless spectroscopy taken as part of the Grism Lens-Amplified Survey from Space (GLASS), we present an extended analysis of the spatial distribution of star formation in 76 galaxies in 10 clusters at 0.3<z<0.7. We use 85 foreground and background galaxies in the same redshift range as a field sample. The samples are well matched in stellar mass (10^8^-10^11^M_{sun}_) and star formation rate (0.5-50M_{sun}_/yr). We visually classify galaxies in terms of broad band morphology, H{alpha} morphology, and likely physical process acting on the galaxy. Most H{alpha} emitters have a spiral morphology (41%+/-8% in clusters, 51%+/-8% in the field), followed by mergers/interactions (28%+/-8%, 31%+/-7%, respectively) and early-type galaxies (remarkably as high as 29%+/-8% in clusters and 15%+/-6% in the field). A diversity of H{alpha} morphologies is detected, suggesting a diversity of physical processes. In clusters, 30%+/-8% of the galaxies present a regular morphology, mostly consistent with star formation diffused uniformly across the stellar population (mostly in the disk component, when present). The second most common morphology (28%+/-8%) is asymmetric/jellyfish, consistent with ram-pressure stripping or other non-gravitational processes in 18%+/-8% of the cases. Ram-pressure stripping appears significantly less prominent in the field (2%+/-2%), where the most common morphology/mechanism appears to be consistent with minor gas-rich mergers or clump accretion. This work demonstrates that while environment-specific mechanisms affect galaxy evolution at this redshift, they are diverse and their effects are subtle. A full understanding of this complexity requires larger samples and detailed and spatially resolved physical models.
- ID:
- ivo://CDS.VizieR/J/A+A/550/A79
- Title:
- H{alpha} and H{beta} lines of northern Be stars
- Short Name:
- J/A+A/550/A79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Be stars are fast rotating early-type emission line stars. It is generally assumed that observed emission is generated in a rotating disk- like envelope, as supported by the observed correlation between the stellar projected rotational velocity v sin i and the width of the emission lines. Then, high resolution spectroscopic observations of Balmer lines profiles play an important role in putting constrains on Be stars modeling. We present Balmer lines spectroscopy for a sample of 48 Be stars. For most of them, H{alpha} and H{beta} have been observed more than two times, in a total period spanning almost two years between 2008 and 2009. Spectral synthesis of the H{alpha} profile has been performed following two steps: photospheric contribution has been computed by using Kurucz's code ATLAS9 and SYNTHE, and disk emission have been derived by the approach of Hummel & Vrancken (1995A&A...302..751H). For 26 out of 48 stars, a modeling of the total H{alpha} emission, i.e. photospheric absorption plus disk net emission, has been attempted. By this modeling we derived an estimation of the disk radius, as well as the inclination angle between rotational axis and line of sight and the base density at the stellar equator. We also discussed, for the stars observed more than once, the variability of H{alpha} and H{beta} for what concerns both the equivalent width and the spectral profile. We found 16 stars with variable equivalent width and 7 stars with clear sign of profile variations. For all the stars of our sample we derive all the fundamental astrophysical quantities, such as: effective temperature, gravity, and projected rotational velocity. We found 13 stars which equivalent width is variable with a confidence level greater than 80% and 7 object for which spectral profiles show change with time. According to the classification scheme commonly used in literature, we classified 16 stars as belonging to class 1, 13 to class 2, 11 are shell stars, 6 objects do not show net emission, and 2 stars display transition from class 1 and 2. For the class 1 stars, we confirm the correlation between vsini and peak separation. concerning the geometry of the disk, we derived the inclination angle between rotational axis and line of sight, the base density at the stellar equator, and the radius. The maximum concentration of stars occur for disk dimensions ranging in the interval of 6 to 8 stellar radii and for inclination angles going from 23{deg} to 35{deg}.
