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1041. M giants spectra and photometry
ID:
ivo://CDS.VizieR/J/A+AS/105/311
Title:
M giants spectra and photometry
Short Name:
J/A+AS/105/311
Date:
21 Oct 2021
Publisher:
CDS
Description:
From a sample of 97 very bright M-giant stars in the Solar neighbourhood, high-quality `intrinsic' spectra in the spectral range [380-900]nm for all M-spectral subclasses of the Case and MK classification systems are obtained. The results are fitted to photospheric synthetic spectra in the range [99-12500]nm in order to infer the corresponding continua. The synthetic spectra are also compared to the intrinsic spectra. The effective temperatures are derived and mathematical spectral classification criteria are found. The (UB)j(VRI)c(JHKLM)eso photometric data of the sample are also given.
1042. M giant stars in the Sagittarius dwarf galaxy. V.
ID:
ivo://CDS.VizieR/J/ApJ/670/346
Title:
M giant stars in the Sagittarius dwarf galaxy. V.
Short Name:
J/ApJ/670/346
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present reliable measurements of the metallicity distribution function (MDF) at different points along the tidal stream of the Sagittarius (Sgr) dwarf spheroidal (dSph) galaxy, based on high-resolution, echelle spectroscopy of candidate M giant members of the Sgr system.
1043. MgII absorbing gas around galaxies
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).
1044. MgII absorption systems for Flat-Spectrum Radio QSOs
ID:
ivo://CDS.VizieR/J/ApJ/754/38
Title:
MgII absorption systems for Flat-Spectrum Radio QSOs
Short Name:
J/ApJ/754/38
Date:
21 Oct 2021
Publisher:
CDS
Description:
The conventional wisdom that the rate of incidence of MgII absorption systems, dN/dz (excluding "associated systems" having a velocity {beta}c relative to the active galactic nucleus (AGN) of less than ~5000km/s), is totally independent of the background AGNs has been challenged by a recent finding that dN/dz for strong MgII absorption systems toward distant blazars is 2.2+/-^0.8^_0.6_ times the value known for normal optically selected quasars (QSOs). This has led to the suggestion that a significant fraction of even the absorption systems with {beta} as high as ~0.1 may have been ejected by the relativistic jets in the blazars, which are expected to be pointed close to our direction. Here, we investigate this scenario using a large sample of 115 flat-spectrum radio-loud quasars (FSRQs) that also possess powerful jets, but are only weakly polarized. We show, for the first time, that dN/dz toward FSRQs is, on the whole, quite similar to that known for QSOs and that the comparative excess of strong MgII absorption systems seen toward blazars is mainly confined to {beta}<0.15. The excess relative to FSRQs probably results from a likely closer alignment of blazar jets with our direction; hence, any gas clouds accelerated by them are more likely to be on the line of sight to the active quasar nucleus.
1045. MgII abs. toward SDSS QSOs with rotation measures
ID:
ivo://CDS.VizieR/J/ApJ/890/132
Title:
MgII abs. toward SDSS QSOs with rotation measures
Short Name:
J/ApJ/890/132
Date:
21 Oct 2021
Publisher:
CDS
Description:
We probed the magnetic fields in high-redshift galaxies using excess extragalactic contribution to residual rotation measure (RRM) for quasar sightlines with intervening MgII absorbers. Based on a large sample of 1132 quasars, we have computed RRM distributions broadening using median absolute deviation from the mean ({sigma}_rrm_^md^), and found it to be 17.1+/-0.7rad/m^2^ for 352 sightlines having MgII intervening absorbers in comparison to its value of 15.1+/-0.6rad/m^2^ for 780 sightlines without such absorbers, resulting in an excess broadening ({sigma}_rrm_^ex^) of 8.0+/-1.9rad:m^2^ among these two subsamples. This value of {sigma}_rrm_^ex^, has allowed us to constrain the average strength of magnetic field (rest frame) in high-redshift galaxies responsible for these Mg II absorbers, to be ~1.3+/-0.3{mu}G at a median redshift of 0.92. This estimate of magnetic field is consistent with the reported estimate in earlier studies based on radio-infrared correlation and energy equipartition for galaxies in the local universe. A similar analysis on subsample split based on the radio spectral index, {alpha} (with F_{nu}_{propto}{nu}^{alpha}^), for flat ({alpha}>=-0.3; 315 sources) and steep ({alpha}<=-0.7; 476 sources) spectrum sources shows a significant {sigma}_rrm_^ex^ (at 3.5{sigma} level) for the former and absent in the latter. An anticorrelation found between the {sigma}_rrm_^md^ and percentage polarization (p) with a similar Pearson correlation of -0.62 and -0.87 for subsamples with and without MgII, respectively, suggests the main contribution for decrements in the p value to be intrinsic to the local environment of quasars.
1046. MgII and LRGs cross-correlation analysis
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.
1047. MgII-BAL quasar variability in SDSS spectra
ID:
ivo://CDS.VizieR/J/ApJS/242/28
Title:
MgII-BAL quasar variability in SDSS spectra
Short Name:
J/ApJS/242/28
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present absorption variability results for 134 bona fide MgII broad absorption-line (BAL) quasars at 0.46<=z<=2.3 covering days to ~10yr in the rest frame. We use multiple-epoch spectra from the Sloan Digital Sky Survey, which has delivered the largest such BAL variability sample ever studied. MgII-BAL identifications and related measurements are compiled and presented in a catalog. We find a remarkable time-dependent asymmetry in the equivalent width (EW) variation from the sample, such that weakening troughs outnumber strengthening troughs, the first report of such a phenomenon in BAL variability. Our investigations of the sample further reveal that (i) the frequency of BAL variability is significantly lower (typically by a factor of 2) than that in high-ionization BALQSO samples, (ii) MgII-BAL absorbers tend to have relatively high optical depths and small covering factors along our line of sight, (iii) there is no significant EW-variability correlation between MgII troughs at different velocities in the same quasar, and (iv) the EW-variability correlation between MgII and AlIII BALs is significantly stronger than that between MgII and CIV BALs at the same velocities. These observational results can be explained by a combined transverse-motion/ionization-change scenario, where transverse motions likely dominate the strengthening BALs while ionization changes and/or other mechanisms dominate the weakening BALs.
1048. MgII/FeII absorption profile for 0.3<z<1.4 galaxies
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.
1049. MgII-K line fluxes in cool active and quiet stars
ID:
ivo://CDS.VizieR/J/A+A/430/303
Title:
MgII-K line fluxes in cool active and quiet stars
Short Name:
J/A+A/430/303
Date:
21 Oct 2021
Publisher:
CDS
Description:
The MgIIk emission line is a good indicator of the level of chromospheric activity in late-type stars. We investigate the dependence of this activity indicator on fundamental stellar parameters. To this purpose we use IUE observations of the MgIIk line in 225 late-type stars of luminosity classes I-V, with different levels of chromospheric activity. We first re-analyse the relation between MgIIk line luminosity and stellar absolute magnitude, performing linear fits to the points. The ratio of MgII surface flux to total surface flux is found to be independent of stellar luminosity for evolved stars and to increase with decreasing luminosity for dwarfs. We also analyse the MgIIk line surface flux-metallicity connection.
1050. Mg II K line Wilson-Bappu relationship
ID:
ivo://CDS.VizieR/J/A+A/374/1085
Title:
Mg II K line Wilson-Bappu relationship
Short Name:
J/A+A/374/1085
Date:
21 Oct 2021
Publisher:
CDS
Description:
An investigation is carried out on the Wilson-Bappu effect in the MgII K line at 2796.34{AA}. The work is based on a selection of 230 stars observed by both the IUE and HIPPARCOS satellites, covering a wide range of spectral types (F to M) and absolute visual magnitudes (-5.4<=M_V_<=9.0). A semi-automatic procedure is used to measure the line widths, which applies also in the presence of strong central absorption reversal. The Wilson-Bappu relationship here provided is considered to represent an improvement over previous recent results for the considerably larger data sample used, as well as for a proper consideration of the measurement errors. No evidence has been found for a possible dependence of the WB effect on stellar metallicity and effective temperature.