- ID:
- ivo://CDS.VizieR/J/AJ/158/239
- Title:
- Metal-rich host stars abundances & equivalent widths
- Short Name:
- J/AJ/158/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relationship between the compositions of giant planets and their host stars is of fundamental interest in understanding planet formation. The solar system giant planets are enhanced above solar composition in metals, both in their visible atmospheres and bulk compositions. A key question is whether the metal enrichment of giant exoplanets is correlated with that of their host stars. Thorngren et al. (2016, J/ApJ/831/64) showed that in cool (T_eq_<1000 K) giant exoplanets, the total heavy-element mass increases with total M_p_ and the heavy-element enrichment relative to the parent star decreases with total M_p_. In their work, the host star metallicity was derived from literature [Fe/H] measurements. Here we conduct a more detailed and uniform study to determine whether different host star metals (C, O, Mg, Si, Fe, and Ni) correlate with the bulk metallicity of their planets, using correlation tests and Bayesian linear fits. We present new host star abundances of 19 cool giant planet systems, and combine these with existing host star data for a total of 22 cool giant planet systems (24 planets). Surprisingly, we find no clear correlation between stellar metallicity and planetary residual metallicity (the relative amount of metal versus that expected from the planet mass alone), which is in conflict with common predictions from formation models. We also find a potential correlation between residual planet metals and stellar volatile-to-refractory element ratios. These results provide intriguing new relationships between giant planet and host star compositions for future modeling studies of planet formation.
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- ID:
- ivo://CDS.VizieR/J/ApJ/763/37
- Title:
- Metals in SDSS QSOs. I. 1.5<z<4.5 CIV absorbers
- Short Name:
- J/ApJ/763/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have vastly increased the CIV statistics at intermediate redshift by surveying the thousands of quasars in the Sloan Digital Sky Survey (SDSS) Data-Release 7. We visually verified over 16000 CIV systems with 1.46<z<4.55 - a sample size that renders Poisson error negligible. Detailed Monte Carlo simulations show that we are approximately 50% complete down to rest equivalent widths W_r_{approx}0.6{AA}. We analyzed the sample as a whole and in 10 small redshift bins with approximately 1500 doublets each. The equivalent width frequency distributions f(W_r_) were well modeled by an exponential, with little evolution in shape. In contrast with previous studies that modeled the frequency distribution as a single power law, the fitted exponential gives a finite mass density for the CIV ions. The comoving line density dN_CIV_/dX evolved smoothly with redshift, increasing by a factor of 2.37+/-0.09 from z=4.55-1.96, then plateauing at dN_CIV_/dX~0.34 for z=1.96-1.46. Comparing our SDSS sample with z<1 (ultraviolet) and z>5 (infrared) surveys, we see an approximately 10-fold increase in dN_CIV_/dX over z{approx}6->0, for W_r_>=0.6{AA}. This suggests a monotonic and significant increase in the enrichment of gas outside galaxies over the 12Gyr lifetime of the universe.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/748/131
- Title:
- MgII absorbers in SDSS-DR7 quasar catalog
- Short Name:
- J/ApJ/748/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A few percent of quasars show strong associated Mg II absorption, with velocities (v_off_) lying within a few thousand km/s from the quasar systemic redshift. These associated absorption line (AAL) systems are usually interpreted as absorbers that are either intrinsic to the quasar and its host, or arising from external galaxies clustering around the quasar. Using composite spectra of ~1800 Mg II AAL quasars selected from SDSS DR7 at 0.4<~z<~2, we show that quasars with AALs with v_off_<1500km/s have a prominent excess in [OII]{lambda}3727 emission (detected at >7{sigma}) at rest relative to the quasar host, compared to unabsorbed quasars. We interpret this [OII] excess as due to enhanced star formation in the quasar host. Our results suggest that a significant fraction of AALs with v_off_<1500km/s are physically associated with the quasar and its host. AAL quasars also have dust reddening lying between normal quasars and the so-called dust-reddened quasars. We suggest that the unique properties of AAL quasars can be explained if they are the transitional population from heavily dust-reddened quasars to normal quasars in the formation process of quasars and their hosts. This scenario predicts a larger fraction of young bulges, disturbed morphologies, and interactions of AAL quasar hosts compared to normal quasars. The intrinsic link between associated absorbers and quasar hosts opens a new window to probe massive galaxy formation and galactic-scale feedback processes, and provides a crucial test of the evolutionary picture of quasars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/354/L25
- Title:
- MgII absorbers in SDSS QSOs
- Short Name:
- J/MNRAS/354/L25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the cross-correlation between 212 Mg II quasar absorption systems and ~20000 luminous red galaxies (LRGs) selected from the Sloan Digital Sky Survey Data Release 1 (Cat. <J/AJ/126/2579>) in the redshift range 0.4<=z<=0.8. The Mg II systems were selected to have {lambda}{lambda}2796 and 2803 rest-frame equivalent widths >=1.0{AA} and identifications confirmed by the Fe II {lambda}2600 or Mg I {lambda}2852 lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/161
- Title:
- MgII absorbers in 0.4<z<2.3 SDSS QSOs
- Short Name:
- J/ApJ/779/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed an analysis of over 34000 Mg II doublets at 0.36<z<2.29 in Sloan Digital Sky Survey (SDSS) Data Release 7 quasar spectra; the catalog, advanced data products, and tools for analysis are publicly available. The catalog was divided into 14 small redshift bins with roughly 2500 doublets in each and from Monte Carlo simulations, we estimate 50% completeness at rest equivalent width W_r_{approx}0.8{AA}. The equivalent width frequency distribution is described well by an exponential model at all redshifts, and the distribution becomes flatter with increasing redshift, i.e., there are more strong systems relative to weak ones. Direct comparison with previous SDSS Mg II surveys reveals that we recover at least 70% of the doublets in these other catalogs, in addition to detecting thousands of new systems. We discuss how these surveys came by their different results, which qualitatively agree but because of the very small uncertainties, differ by a statistically significant amount. The estimated physical cross section of Mg II-absorbing galaxy halos increased approximately threefold from z=0.4 to z=2.3, while the W_r_>=1{AA} absorber line density, dN_MgII_/dX, grew by roughly 45%. Finally, we explore the different evolution of various absorber populations --damped Ly{alpha} absorbers, Lyman limit systems, strong C IV absorbers, and strong and weaker MgII systems -- across cosmic time (0<z<6).
- 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/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.
- 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.
- 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.
