- ID:
- ivo://CDS.VizieR/J/AJ/143/14
- Title:
- Lick indices of M31 globular clusters
- Short Name:
- J/AJ/143/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present absorption line indices measured in the integrated spectra of globular clusters both from the Galaxy and from M31. Our samples include 41 Galactic globular clusters, and more than 300 clusters in M31. The conversion of instrumental equivalent widths into the Lick system is described, and zero-point uncertainties are provided. Comparison of line indices of old M31 clusters and Galactic globular clusters suggests an absence of important differences in chemical composition between the two cluster systems. In particular, CN indices in the spectra of M31 and Galactic clusters are essentially consistent with each other, in disagreement with several previous works. We reanalyze some of the previous data, and conclude that reported CN differences between M31 and Galactic clusters were mostly due to data calibration uncertainties. Our data support the conclusion that the chemical compositions of Milky Way and M31 globular clusters are not substantially different, and that there is no need to resort to enhanced nitrogen abundances to account for the optical spectra of M31 globular clusters.
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Search Results
- ID:
- ivo://CDS.VizieR/I/200
- Title:
- Lick Northern Proper Motion: NPM1 Ref. Galaxies
- Short Name:
- I/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Lick Northern Proper Motion (NPM) program measured proper motions, positions, and photographic photometry for some 149,000 stars (NPM1 Catalog) covering the sky outside the Milky Way north of declination 23 degrees. The NPM1 proper motions were measured with respect to an absolute reference frame defined by some 50,000 faint galaxies (mostly 16 < B < 18 mag). The rms position errors for the NPM1 reference galaxies average 0.2 arcsec. The rms errors for the B magnitudes average 0.25 mag. More complete descriptive information is available in the ASCII or LaTeX documentation written by R.B. Hanson (UCO/Lick Obs.).
- ID:
- ivo://CDS.VizieR/J/ApJ/837/120
- Title:
- Lick Observatory Supernova Search (LOSS) revisited
- Short Name:
- J/ApJ/837/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most types of supernovae (SNe) have yet to be connected with their progenitor stellar systems. Here, we reanalyze the 10-year SN sample collected during 1998-2008 by the Lick Observatory Supernova Search (LOSS; see Leaman+, 2011, J/MNRAS/412/1419) in order to constrain the progenitors of SNe Ia and stripped-envelope SNe (SE SNe, i.e., SNe IIb, Ib, Ic, and broad-lined Ic). We matched the LOSS galaxy sample with spectroscopy from the Sloan Digital Sky Survey (SDSS) and measured SN rates as a function of galaxy stellar mass, specific star formation rate, and oxygen abundance (metallicity). We find significant correlations between the SN rates and all three galaxy properties. The SN Ia correlations are consistent with other measurements, as well as with our previous explanation of these measurements in the form of a combination of the SN Ia delay-time distribution and the correlation between galaxy mass and age. The ratio between the SE SN and SN II rates declines significantly in low-mass galaxies. This rules out single stars as SE SN progenitors, and is consistent with predictions from binary-system progenitor models. Using well-known galaxy scaling relations, any correlation between the rates and one of the galaxy properties examined here can be expressed as a correlation with the other two. These redundant correlations preclude us from establishing causality-that is, from ascertaining which of the galaxy properties (or their combination) is the physical driver for the difference between the SE SN and SN II rates. We outline several methods that have the potential to overcome this problem in future works.
- ID:
- ivo://CDS.VizieR/J/ApJ/622/217
- Title:
- Light and motion in the local volume
- Short Name:
- J/ApJ/622/217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using high-quality data on 149 galaxies within 10Mpc, I find no correlation between luminosity and peculiar velocity at all. There is no unequivocal sign on scales of 12Mpc of the expected gravitational effect of the brightest galaxies, in particular infall toward groups, or of infall toward the supergalactic plane on any scale. Either dark matter is not distributed in the same way as luminous matter in this region, or peculiar velocities are not due to fluctuations in mass. The sensitivity of peculiar velocity studies to the background model is highlighted.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/4590
- Title:
- Light curves of RR Lyrae variables in M31
- Short Name:
- J/MNRAS/478/4590
- Date:
- 10 Dec 2021 13:45:59
- Publisher:
- CDS
- Description:
- We present an analysis of M31 RR Lyrae stars in six different fields using archival imaging from the Hubble Space Telescope. Published data for M31, M33, and several M31 dwarf spheroidal galaxies are also used to study the global properties of RR Lyrae in these systems. From the properties of RR Lyrae stars, we found that the majority of M31 and M33 RRLs are of Oosterhoff I (OoI),while those in M31 dSphs are of Oosterhoff intermediate. The main parameter affecting these Oosterhoff types is likely to be metallicity. Metallicity also plays a role in the lack of RRLs in the high amplitude short period(HASP, defined as those with P<=0.48 and A_V_>=0.75mag) variables in M31 dSphs. This difference in the properties of RRLs between their parent galaxy and satellites, as well as the lack of RRLs in the HASP region in dSphs can also be observed in the Milky Way (MW). Therefore, systems like these dSphs are unlikely to be the main building blocks of the M31 and MW halo.
- ID:
- ivo://CDS.VizieR/J/ApJ/795/L21
- Title:
- Limits on gamma-ray emission from galaxy clusters
- Short Name:
- J/ApJ/795/L21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy clusters are predicted to produce {gamma}-rays through cosmic ray interactions and/or dark matter annihilation, potentially detectable by the Fermi Large Area Telescope (Fermi-LAT). We present a new, independent stacking analysis of Fermi-LAT photon count maps using the 78 richest nearby clusters (z<0.12) from the Two Micron All Sky Survey cluster catalog. We obtain the lowest limit on the photon flux to date, 2.3x10^-11^ photons/cm2/s (95% confidence) per cluster in the 0.8-100 GeV band, which corresponds to a luminosity limit of 3.5x10^44^ photons/s. We also constrain the emission limits in a range of narrower energy bands. Scaling to recent cosmic ray acceleration and {gamma}-ray emission models, we find that cosmic rays represent a negligible contribution to the intra-cluster energy density and gas pressure.
- ID:
- ivo://CDS.VizieR/J/ApJ/714/1441
- Title:
- Linearity of the cosmic expansion field
- Short Name:
- J/ApJ/714/1441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Particularly accurate relative distances are compiled and homogenized for (1) 246 Type Ia supernovae and 35 clusters with v<30000km/s, and (2) relatively nearby galaxies with 176 tip of the red-giant branch and 30 Cepheid distances. The 487 objects define a tight Hubble diagram from 300-30000km/s implying individual distance errors of <~7.5%. Here the velocities are corrected for Virgocentric steaming (locally 220km/s) and -if v_220_>3500km/s- for a 495km/s motion of the Local Supercluster toward the warm cosmic microwave background (CMB) pole at l=275, b=12; local peculiar motions are averaged out by large numbers.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/3
- Title:
- Linear structural param. of SDSS+UKIDSS+WISE gal.
- Short Name:
- J/ApJS/244/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate measurements of galaxy structure are prerequisites for quantitative investigation of galaxy properties or evolution. Yet galaxy inclination, through projection and varying dust effects, strongly affects many commonly used metrics of galaxy structure. Here we demonstrate that collapsing a galaxy's light distribution onto its major axis gives a "linear brightness profile" that is unaffected by projection. In analogy to widely used half-light radius and concentrations, we use two metrics to describe this light distribution: x_50_, the linear distance containing half of the galaxy's luminosity, and c_x_=x_90_/x_50_, the ratio between the 90% light distance and the 50% light distance. In order to minimize the effects of dust, we apply this technique to a diverse sample of galaxies with moderately deep and high-resolution K-band imaging from the UKIDSS Large Area Survey. Using simulated galaxy images, we find that while our measurements are primarily limited by the surface brightness in the outer parts of galaxies, most local galaxies have high enough surface brightnesses to result in reliable measurements. When applied to real data, our metrics vary from face-on to edge-on by typically ~5% in c_x_ and ~12% in x_50_, representing factors of several to 10 improvement over existing optical and some infrared catalog measures of galaxy structure. We release a sample of 23804 galaxies with inclination-independent and dust-penetrated observational proxies for stellar mass, specific star formation rate, half-light size, and concentration.
- ID:
- ivo://CDS.VizieR/J/ApJ/621/673
- Title:
- Line indices for 124 early-type galaxies
- Short Name:
- J/ApJ/621/673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of this paper is to set constraints on the epochs of early-type galaxy formation through the "archaeology" of the stellar populations in local galaxies. Using our models of absorption-line indices that account for variable abundance ratios, we derive ages, total metallicities, and element ratios of 124 early-type galaxies in high- and low-density environments. The data are analyzed by comparison with mock galaxy samples created through Monte Carlo simulations taking the typical average observational errors into account, in order to eliminate artifacts caused by correlated errors.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/1314
- Title:
- Line list for seven target PAndAS clusters
- Short Name:
- J/MNRAS/448/1314
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detailed chemical abundances are presented for seven M31 outer halo globular clusters (with projected distances from M31 greater than 30 kpc), as derived from high-resolution integrated light spectra taken with the Hobby-Eberly Telescope. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS) - this paper presents the first determinations of integrated Fe, Na, Mg, Ca, Ti, Ni, Ba, and Eu abundances for these clusters. Four of the target clusters (PA06, PA53, PA54, and PA56) are metal poor ([Fe/H]< -1.5), {alpha}-enhanced (though they are possibly less {alpha}-enhanced than Milky Way stars at the 1{sigma} level), and show signs of star-to-star Na and Mg variations. The other three globular clusters (H10, H23, and PA17) are more metal rich, with metallicities ranging from [Fe/H]=-1.4 to -0.9. While H23 is chemically similar to Milky Way field stars, Milky Way globular clusters, and other M31 clusters, H10 and PA17, have moderately low [Ca/Fe], compared to Milky Way field stars and clusters. Additionally, PA17's high [Mg/Ca] and [Ba/Eu] ratios are distinct from Milky Way stars, and are in better agreement with the stars and clusters in the Large Magellanic Cloud. None of the clusters studied here can be conclusively linked to any of the identified streams from PAndAS; however, based on their locations, kinematics, metallicities, and detailed abundances, the most metal-rich PAndAS clusters H23 and PA17 may be associated with the progenitor of the Giant Stellar Stream, H10 may be associated with the SW cloud, and PA53 and PA56 may be associated with the eastern cloud.
