- ID:
- ivo://CDS.VizieR/J/AJ/133/2825
- Title:
- Star beyond the NLTT catalog
- Short Name:
- J/AJ/133/2825
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have combined near-infrared data from the Two Micron All Sky Survey with ancillary optical data to identify previously unrecognized proper-motion stars that have colors and magnitudes consistent with nearby M dwarfs. We present follow-up observations of 392 stars from that sample, including ~200 stars discussed here for the first time. Our distance estimates, based primarily on spectroscopic parallaxes, place 123 stars within 20pc of the Sun. One hundred and seventy-six stars exhibit H{alpha} emission, and 82 stars have plausible X-ray counterparts from ROSAT observations.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/686/127
- Title:
- Starbursts luminosities based on PAH
- Short Name:
- J/ApJ/686/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A summary of starburst luminosities based on polycyclic aromatic hydrocarbon (PAH) features is given for 243 starburst galaxies with 0<z<2.5, observed with the Spitzer Infrared Spectrograph. Luminosity {nu}L_{nu}_(7.7um) for the peak luminosity of the 7.7um PAH emission feature is found to scale as log[{nu}L_{nu}_(7.7{mu}m)]=44.63(+/-0.09)+2.48(+/-0.28)log(1+z) for the most luminous starbursts observed. Empirical calibrations of {nu}L_{nu}_(7.7um) are used to determine bolometric luminosity L_IR_ and the star formation rate (SFR) for these starbursts. The most luminous starbursts found in this sample have logL_IR_=45.4(+/-0.3)+2.5(+/-0.3)log(1+z), in ergs/s, and the maximum star formation rates for starbursts in units of M_{sun}_/yr are log(SFR)=2.1(+/-0.3)+2.5(+/-0.3)log(1+z), up to z=2.5. The exponent for pure luminosity evolution agrees with optical and radio studies of starbursts but is flatter than previous results based in infrared source counts. The maximum star formation rates are similar to the maxima determined for submillimeter galaxies; the most luminous individual starburst included within the sample has logL_IR_=46.9, which gives an SFR=3.4x10^3^M_{sun}/yr. Description: In this paper, we assemble data from 14 different Spitzer/IRS (InfraRed Spectrograph) programs (listed in "Ref" column of table1) to summarize a wide variety of sources having strong PAH spectral features, providing a total of 243 sources.
- ID:
- ivo://CDS.VizieR/J/ApJS/187/149
- Title:
- StarCAT: STIS UV echelle spectra of stars
- Short Name:
- J/ApJS/187/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- StarCAT is a catalog of high resolution ultraviolet spectra of objects classified as "stars," recorded by Space Telescope Imaging Spectrograph (STIS) during its initial seven years of operations (1997-2004). StarCAT is based on 3184 echelle observations of 545 distinct targets, with a total exposure duration of 5.2Ms. For many of the objects, broad ultraviolet coverage has been achieved by splicing echellegrams taken in two or more FUV (1150-1700{AA}) and/or NUV (1600-3100{AA}) settings. In cases of multiple pointings on conspicuously variable sources, spectra were separated into independent epochs. Otherwise, different epochs were combined to enhance the signal-to-noise ratio (S/N). A post-facto correction to the "calstis" pipeline data sets compensated for subtle wavelength distortions identified in a previous study of the STIS calibration lamps. An internal "fluxing" procedure yielded coherent spectral energy distributions (SEDs) for objects with broadly overlapping wavelength coverage. The best StarCAT material achieves 300m/s internal velocity precision; absolute accuracy at the 1km/s level; photometric accuracy of order 4%; and relative flux precision several times better (limited mainly by knowledge of SEDs of UV standard stars). While StarCAT represents a milestone in the large-scale post-processing of STIS echellegrams, a number of potential improvements in the underlying "final" pipeline are identified.
- ID:
- ivo://CDS.VizieR/J/A+A/609/A13
- Title:
- Star cluster Gaia 1 stars equivalent widths
- Short Name:
- J/A+A/609/A13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Star clusters, particularly those objects in the disk-bulge-halo interface are as yet poorly charted, despite the fact that they carry important information about the formation and the structure of the Milky Way. Here, we present a detailed chemical abundance study of the recently discovered object Gaia 1. Photometry has previously suggested it as an intermediate-age, moderately metal-rich system, although the exact values for its age and metallicity remained ambiguous in the literature. We measured detailed chemical abundances of 14 elements in four red giant members, from high-resolution (R=25000) spectra that firmly establish Gaia 1 as an object associated with the thick disk. The resulting mean Fe abundance is -0.62+/-0.03(stat.)+/-0.10(sys.) dex, which is more metal-poor than indicated by previous spectroscopy from the literature, but it is fully in line with values from isochrone fitting. We find that Gaia 1 is moderately enhanced in the {alpha}-elements, which allowed us to consolidate its membership with the thick disk via chemical tagging. The cluster's Fe-peak and neutron-capture elements are similar to those found across the metal-rich disks, where the latter indicate some level of s-process activity. No significant spread in iron nor in other heavy elements was detected, whereas we find evidence of light-element variations in Na, Mg, and Al. Nonetheless, the traditional Na-O and Mg-Al (anti-)correlations, typically seen in old globular clusters, are not seen in our data. This confirms that Gaia 1 is rather a massive and luminous open cluster than a low-mass globular cluster. Finally, orbital computations of the target stars bolster our chemical findings of Gaia 1's present-day membership with the thick disk, even though it remains unclear which mechanisms put it in that place.
- ID:
- ivo://CDS.VizieR/J/ApJ/894/57
- Title:
- Star formation activities in MaNGA low-mass galaxies
- Short Name:
- J/ApJ/894/57
- Date:
- 03 Dec 2021 00:39:35
- Publisher:
- CDS
- Description:
- We explore the environmental influences on the star formation (SF) in low-mass galaxies with stellar mass 8<=log(M_*_/M_{sun}_)<=10 at a redshift of 0.01<z<0.07. We identify the neighboring galaxies for our sample using the spectroscopically observed galaxies in the Sloan Digital Sky Survey (SDSS). Our 287 selected pair candidates have a neighboring galaxy with a stellar mass ratio of M_Neighbor_/M_Candidate_<=4 at a projected separation within d_proj_<=1500kpc and a line-of-sight kinematic separation of {Delta}v_LOS_<=300km/s. Our control galaxies are isolated from other galaxies within a projected radius of 1500kpc. All selected galaxies in our sample are spectroscopically observed by the fourth generation of SDSS/Mapping Nearby Galaxies at Apache Point Observatory (SDSS-IV/MaNGA) integral field spectroscopy survey. We radially bin our selected galaxies into three regions with a radial distance of 0<=R/R_e_<=0.5 (inner), 0.5<=R/R_e_<=1.0 (middle), and 1.0<=R/R_e_<=1.5 (outer), in which R_e_ is the effective radius at where the galaxy emit half of its light. We conclude that the SF activities in low-mass galaxies are affected by their environmental conditions when {Delta}v_LOS_<=100km/s at d_proj_<=400kpc. We use stellar-mass-weighted SF rate surface density ({Sigma}SFR/M_*_) to describe the SF strength in each radially binned region. For the pair candidates with 0.25<=M_Neighbor_/M_Candidate_<=4 at d_proj_<=100kpc and {Delta}v_LOS_<=100km/s, we observe an SF enhancement of f_{Delta}SF_=1.75+/-0.96 (f_{Delta}SF_=[({Sigma}SFR/M_*_)_Pair_-({Sigma}SFR/M_*_)_Control,mean_] /({Sigma}SFR/M_*_)_Control,mean_) in their inner regions, which decreases with increasing galactic radii.
- ID:
- ivo://CDS.VizieR/J/A+AS/130/251
- Title:
- Star Formation in Early-type galaxies
- Short Name:
- J/A+AS/130/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper is the first of a series (Longhetti et al., 1998A&AS..130..267L, 1998b (Paper III) in press) dedicated to the study of the star formation history in early-type galaxies which show fine structures and/or interaction signatures. It presents nuclear line-strength indices for a sample composed of 21 shell galaxies, from the Malin & Carter (1983ApJ...274..534M) southern survey, and 30 members of isolated interacting pairs, from the Reduzzi & Rampazzo (1995ApL....30....1R) catalogue, located in low density environments. The spectral range covers 3700{AA}<{lambda}<5700{AA} at 2.1{AA}FWHM resolution. We measure 16 red ({lambda}>4200{AA}) indices defined by the Lick Group. Measures have been transformed into the Lick-IDS ``standard'' system. The procedure has been tested on a set of 5 elliptical galaxies selected from the Gonzalez (1993, Ph.D. thesis) sample. We derive also three blue ({lambda}<4200) indices, namely {DELTA}(4000{AA}) defined by Hamilton (1985ApJ...297..371H), H+K(CaII) and Hdelta/FeI defined by Rose (1984AJ.....89.1238R, 1985AJ.....90.1927R). Blue indices are correlated to the age of the last starburst occurred in a galaxy (Leonardi & Rose, 1996AJ....111..182L). The indices determination, the estimate of the measurement errors and the correction for the galaxies velocity dispersions are discussed in detail. In the Appendix A we present the indices for a set of hot stars (T>10000K) which may be used for extending, toward high temperatures, Worthey (1992, Ph.D. Thesis) fitting functions.
- ID:
- ivo://CDS.VizieR/J/A+A/345/419
- Title:
- Star formation in early-type galaxies
- Short Name:
- J/A+A/345/419
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the star formation properties of a sample of 21 shell galaxies and 30 early-type galaxies members of interacting pairs, located in low density environments (Longhetti et al., 1998, Cat. <J/A+AS/130/251>, 1998A&AS..130..267L). The study is based on new models developed to interpret the information coming from `blue' H{delta}FeI, H+K(CaII) and D4000 line-strength indices proposed by Rose (1984AJ.....89.1238R; 1985AJ.....90.1927R) and Hamilton (1985ApJ...297..371H). We find that the last star forming event that occurred in the nuclear region of shell galaxies is statistically old (from 0.1 up to several Gyr) with respect to the corresponding one in the sub-sample of pair galaxies (<0.1Gyr or even ongoing star formation). If the stellar activity is somehow related to the formation of shells, as predicted by several dynamical models of galaxy interaction, shells have to be considered long lasting structures. Since pair members show evidence of very recent star formation, we suggest that either large reservoirs of gas have to be present to maintain active star formation, if these galaxies are on periodic orbits, or most of the pair members in the present sample are experiencing unbound encounters.
- ID:
- ivo://CDS.VizieR/J/ApJ/708/841
- Title:
- Star formation in E/S0 galaxies
- Short Name:
- J/ApJ/708/841
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent work has identified a population of low-redshift E/S0 galaxies that lie on the blue sequence in color versus stellar mass parameter space, where spiral galaxies typically reside. While high-mass blue-sequence E/S0s often resemble young merger or interaction remnants likely to fade to the red sequence, we focus on blue-sequence E/S0s with lower stellar masses (M_*_<a fewx10^10^M_{sun}_), which are characterized by fairly regular morphologies and low-density field environments where fresh gas infall is possible. This population may provide an evolutionary link between early-type galaxies and spirals through disk regrowth. Focusing on atomic gas reservoirs, we present new GBT HI data for 27 E/S0s on both sequences as well as a complete tabulation of archival HI data for other galaxies in the Nearby Field Galaxy Survey. Normalized to stellar mass, the atomic gas masses for 12 of the 14 blue-sequence E/S0s range from 0.1 to >1.0, demonstrating that morphological transformation is possible if the detected gas can be converted into stars. These gas-to-stellar mass ratios are comparable to those of spiral and irregular galaxies and have a similar dependence on stellar mass.
- ID:
- ivo://CDS.VizieR/J/A+A/634/A95
- Title:
- Star formation in the blue compact dwarf Mrk 900
- Short Name:
- J/A+A/634/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low-luminosity, active star-forming blue compact galaxies (BCGs) are excellent laboratories for investigating the process of star formation on galactic scales and probing the interplay between massive stars and the surrounding interstellar (or intergalactic) medium. We investigated the morphology, structure, and stellar content of the Blue Compact Galaxy Mrk 900, combining optical integral field observations obtained with VIMOS at the VLT and deep broad-band photometry taken at the 2.5 m NOT telescope. From the integral field data, we built continuum, emission, and diagnostic line ratio maps and produced velocity and velocity dispersion maps. We also generated the integrated spectrum of the major HII regions and the nuclear area to determine reliable physical parameters and oxygen abundances. The broad-band data, tracing the galaxy up to radius 4 kpc, allowed us to investigate the properties of the low surface brightness underlying stellar host. We disentangle two different stellar components in Mrk 900: a young population, which resolves into individual stellar clusters with ages ~5.5-6.6Myr and extends about 1 kpc along the galaxy minor axis, is placed on top of a rather red and regular shaped underlying stellar host, several Gyr old. We find evidence of a substantial amount of dust and an inhomogeneous extinction pattern, with a dust lane crossing the central starburst. Mrk 900 displays overall rotation, although distorted in the central, starburst regions; the dispersion velocity map is highly inhomogeneous, with values increasing up to 60km/s at the periphery of the SF regions, where we also find hints of the presence of shocks. Our observational results point to an interaction or merger with a low-mass object or infalling gas as plausible trigger mechanisms for the present starburst event.
- ID:
- ivo://CDS.VizieR/J/A+A/599/A95
- Title:
- Star formation in z~1.5 quiescent galaxies
- Short Name:
- J/A+A/599/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 34 spectroscopically confirmed BzK-selected ~10^11^M_{sun}_ quiescent galaxies (pBzK) in the COSMOS field. The targets were initially observed with VIMOS on the VLT to facilitate the calibration of the photometric redshifts of massive galaxies at z>~1.5. Here we describe the reduction and analysis of the data, and the spectrophotometric properties of these pBzK galaxies. In particular, using a spatially resolved median 2D spectrum, we find that the fraction of stellar populations with ages <1Gyr is at least 3 times higher in the outer regions of the pBzK galaxies than in their cores. This results in a mild age gradient of {DELTA}age<=0.4Gyr over ~6kpc and suggests either the occurrence of widespread rejuvenation episodes or that inside-out quenching played a role in the passivization of this galaxy population. We also report on low-level star formation rates derived from the [OII]3727{AA} emission line, with SFR_OII_~3.7-4.5M_{sun}_/yr. This estimate is confirmed by an independent measurement on a separate sample of similarly-selected quiescent galaxies in the COSMOS field, using stacked far-infrared data (SFR_FIR_~2-4M_{sun}_/yr). This second, photometric sample also displays significant excess at 1.4GHz, suggestive of the presence of radio-mode AGN activity.
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