- ID:
- ivo://CDS.VizieR/J/ApJ/711/350
- Title:
- Metal-poor giant Boo-1137 abundances
- Short Name:
- J/ApJ/711/350
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution (R~40000), high-signal-to-noise ratio (20-90) spectra of an extremely metal-poor giant star Boo-1137 in the "ultra-faint" dwarf spheroidal galaxy (dSph) Bootes I, absolute magnitude M_V_~-6.3. We derive an iron abundance of [Fe/H]=-3.7, making this the most metal-poor star as yet identified in an ultra-faint dSph. Our derived effective temperature and gravity are consistent with its identification as a red giant in Bootes I. Abundances for a further 15 elements have also been determined. Comparison of the relative abundances, [X/Fe], with those of the extremely metal-poor red giants of the Galactic halo shows that Boo-1137 is "normal" with respect to C and N, the odd-Z elements Na and Al, the iron-peak elements, and the neutron-capture elements Sr and Ba, in comparison with the bulk of the Milky Way halo population having [Fe/H]<~-3.0. The {alpha}-elements Mg, Si, Ca, and Ti are all higher by {Delta}[X/Fe]~0.2 than the average halo values. Monte Carlo analysis indicates that {Delta}[{alpha}/Fe] values this large are expected with a probability ~0.02. The elemental abundance pattern in Boo-1137 suggests inhomogeneous chemical evolution, consistent with the wide internal spread in iron abundances we previously reported.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/452/4326
- Title:
- Metal-rich damped Ly{alpha} systems at z~2
- Short Name:
- J/MNRAS/452/4326
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using our sample of the most metal-rich damped Lyman {alpha} systems (DLAs) at z_abs_~2, and two literature compilations of chemical abundances in 341 DLAs and 2818 stars, we present an analysis of the chemical composition of DLAs in the context of the Local Group. The metal-rich sample of DLAs at z_abs~2 probes metallicities as high as the Galactic disc and the most metal-rich dwarf spheroidals (dSphs), permitting an analysis of many elements typically observed in DLAs (Fe, Zn, Cr, Mn, Si, and S) in comparison to stellar abundances observed in the Galaxy and its satellites (in particular dSphs). Our main conclusions are: (1) non-solar [Zn/Fe] abundances in metal-poor Galactic stars and in dSphs over the full metallicity range probed by DLAs, suggest that Zn is not a simple proxy for Fe in DLAs and therefore not a suitable indicator of dust depletion. After correcting for dust depletion, the majority of DLAs have subsolar [Zn/Fe] similar to dSphs; (2) at [Fe/H]~-0.5, a constant [Mn/Fe]~-0.5 and near-solar [{alpha}/Fe] (requiring an assumption about dust depletion) are in better agreement with dwarf galaxies than Galactic disc stars; (3) [{alpha}/Zn] is usually solar or subsolar in DLAs. However, although low ratios of [{alpha}/Fe] are usually considered more 'dwarf-like' than `Milky Way-like', subsolar [Zn/Fe] in Local Group dwarfs leads to supersolar [{alpha}/Zn] in the dSphs, in contrast with the DLAs. Therefore, whilst DLAs exhibit some similarities with the Local Group dwarf population, there are also notable differences.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/904
- Title:
- Metal-rich dwarf galaxies from SDSS-DR4
- Short Name:
- J/ApJ/685/904
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified a sample of 41 low-mass high-oxygen abundance outliers from the mass-metallicity relation of star-forming galaxies measured by Tremonti et al. (2004ApJ...613..898T). These galaxies, which have 8.6<12+log(O/H)<9.3 over a range of -14.4>M_B_>-19.1 and 7.4<log(M_*_/M_{sun}_)<10, are surprisingly nonpathological. They have typical specific star formation rates, are fairly isolated, and, with few exceptions, have no obvious companions. Morphologically, they are similar to dwarf spheroidal or dwarf elliptical galaxies. We predict that their observed high oxygen abundances are due to relatively low gas fractions, concluding that these are transitional dwarf galaxies nearing the end of their star formation activity.
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/1625
- Title:
- Method for orientation angles of galaxies
- Short Name:
- J/MNRAS/403/1625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A method is proposed for the determination of the position and inclination angles of the plane of a spiral galaxy based on the assumption that every spiral arm is a monotonic function of the radius against azimuthal angle. This method may yield more accurate results than the more commonly employed isophote method, which is subject to a number of drawbacks. Analytical study, calibration against other methods and examples of application of the proposed method to real galaxies are presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/808/108
- Title:
- M2FS stellar spectroscopy of Reticulum 2
- Short Name:
- J/ApJ/808/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from spectroscopic observations with the Michigan/Magellan Fiber System (M2FS) of 182 stellar targets along the line of sight (LOS) to the newly discovered "ultrafaint" object Reticulum 2 (Ret 2). For 37 of these targets, the spectra are sufficient to provide simultaneous estimates of LOS velocity ({nu}i_los_, median random error {delta}_{nu}los_=1.4km/s), effective temperature (T_eff_, {delta}_Tef_=478K), surface gravity (logg, {delta}_logg_=0.63dex), and iron abundance ([Fe/H], {delta}_[Fe/H]_=0.47dex). We use these results to confirm 17 stars as members of Ret 2. From the member sample we estimate a velocity dispersion of {sigma}_{nu}los_=3.6_-0.7_^+1.0^km/s about a mean of <{nu}_los_>=64.3_1.2_^+1.2^km/s in the solar rest frame (~-90.9km/s in the Galactic rest frame), and a metallicity dispersion of {sigma}_[Fe/H]_=0.49_-0.14_^+0.19^dex about a mean of <[Fe/H]_>=-2.58_-0.33_^+0.34^. These estimates marginalize over possible velocity and metallicity gradients, which are consistent with zero. Our results place Ret 2 on chemodynamical scaling relations followed by the Milky Way's dwarf-galactic satellites. Under assumptions of dynamic equilibrium and negligible contamination from binary stars --both of which must be checked with deeper imaging and repeat spectroscopic observations-- the estimated velocity dispersion suggests a dynamical mass of M(R_h_)~5R_h_{sigma}_{nu}los_^2^/(2G)=2.4_-0.8_^+1.4^x10^5^M_{sun}_ enclosed within projected halflight radius R_h_~32pc, with mass-to-light ratio ~2M(R_h_)/L_V_=467_-168_^+286^ in solar units.
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/3811
- Title:
- M33 GALEX catalogue of UV point sources
- Short Name:
- J/MNRAS/450/3811
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The hottest stars (>10000K), and by extension typically the most massive ones, are those that will be prevalent in the ultraviolet (UV) portion of the electromagnetic spectrum, and we expect to numerous B, O and WR (WR) stars to be bright in UV data. In this paper, we update the previous point source UV catalogue of M33, created using the Ultraviolet Imaging Telescope (UIT), using data from the Galaxy Evolution Explorer (GALEX). We utilize point spread function photometry to optimally photometer sources in the crowded regions of the galaxy, and benefit from GALEX's increased sensitivity compared to UIT. We match our detections with data from the Local Group Galaxies Survey to create a catalogue with photometry spanning from the far-UV through the optical for a final list of 24738 sources. All of these sources have far-UV (FUV; 1516{AA}), near-UV (NUV; 2267{AA}) and V data, and a significant fraction also have U, B, R and I data as well. We also present an additional 3000 sources that have no matching optical counterpart. We compare all of our sources to a catalogue of known WR stars in M33 and find that we recover 114 of 206 stars with spatially-coincident UV point sources. Additionally, we highlight and investigate those sources with unique colours as well as a selection of other well-studied sources in M33.
- ID:
- ivo://CDS.VizieR/J/ApJ/724/L176
- Title:
- MgII absorbing gas around galaxies
- Short Name:
- J/ApJ/724/L176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the connections between ongoing star formation, galaxy mass, and extended halo gas, in order to distinguish between starburst-driven outflows and infalling clouds that produce the majority of observed MgII absorbers at large galactic radii (>~10h^-1^kpc) and to gain insights into halo gas contents around galaxies. We present new measurements of total stellar mass (M_star_), H{alpha} emission line strength (EW(H{alpha})), and specific star formation rate (sSFR) for the 94 galaxies described by Chen et al.'s 2010 paper (Cat. J/ApJ/714/1521).
- ID:
- ivo://CDS.VizieR/J/ApJ/698/819
- Title:
- MgII and LRGs cross-correlation analysis
- Short Name:
- J/ApJ/698/819
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the cross-correlation of MgII({lambda}2796, 2803) quasar absorption systems with luminous red galaxies (LRGs) from the Fifth Data Release (DR5) of the Sloan Digital Sky Survey. The absorption line sample consists of 2705 unambiguously intervening MgII absorption systems, detected at a 4{sigma} level, covering a redshift range (0.36<=z_abs_<=0.8) and a rest equivalent-width range of 0.8{AA}<=W^{lambda}2796^_r_<=5.0{AA}. We cross-correlate these absorbers with 1495604 LRGs with accurate photometric redshifts in the same redshift range and examine the relationship of MgII equivalent width and clustering amplitude.
- ID:
- ivo://CDS.VizieR/J/ApJ/794/156
- Title:
- MgII/FeII absorption profile for 0.3<z<1.4 galaxies
- Short Name:
- J/ApJ/794/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze Mg II {lambda}{lambda}2796, 2803 and Fe II {lambda}{lambda}2586, 2600 absorption profiles in individual spectra of 105 galaxies at 0.3<z<1.4. The galaxies, drawn from redshift surveys of the GOODS fields and the Extended Groth Strip, sample the range in star formation rates (SFRs) occupied by the star-forming sequence with stellar masses log M_*_/M_{sun}_>~9.6 down to SFR>~2 M_{sun}_/yr at 0.3<z<0.7. Using the Doppler shifts of Mg II and Fe II absorption as tracers of cool gas kinematics, we detect large-scale winds in 66+/-5% of the galaxies. Hubble Space Telescope Advanced Camera for Surveys imaging and our spectral analysis indicate that the outflow detection rate depends primarily on galaxy orientation: winds are detected in ~89% of galaxies having inclinations (i) <30{deg} (face-on), while the wind detection rate is ~45% in objects having i>50{deg} (edge-on). Combined with the comparatively weak dependence of wind detection rate on intrinsic galaxy properties, this implies that biconical outflows are ubiquitous in normal, star-forming galaxies at z~0.5. We find that wind velocity is correlated with galaxy M_*_ at 3.4{sigma} significance, while outflow equivalent width is correlated with SFR at 3.5{sigma} significance, suggesting hosts with higher SFR launch more material and/or generate a larger velocity spread for the absorbing clouds. Assuming the gas is driven into halos with isothermal density profiles, the wind velocities (~200-400 km/s) permit escape from the halo potentials only for the lowest-M_*_systems in the sample. However, the gas carries sufficient energy to reach distances >~50 kpc, and may therefore be a viable source of material for the massive, cool circumgalactic medium around bright galaxies at z~0.
- ID:
- ivo://CDS.VizieR/J/A+AS/136/519
- Title:
- Mg2 indices for early-type galaxies
- Short Name:
- J/A+AS/136/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 210 new measurements of the central absorption line-strength Mg_2_ index for 87 early-type galaxies drawn from the Prugniel & Simien (1996, Cat. <J/A+A/309/749>) sample. 28 galaxies were not observed before. The results are compared to measurements published previously as available in HYPERCAT, and rescaled to the Lick system. The mean individual internal error on these measurements is 0.009mag+/-0.003mag and the mean external error is 0.012mag+/-0.002mag for this series of measurements. These data are also available from HYPERCAT.
