Related papers: A new calibration for the Blue Horizontal Branch
Based on photometric data of the central parts of eight globular clusters and one open cluster presented by An and his collaborators, we select red horizontal branch (RHB) stars in the (g-r)0-g0 diagram and make a statistical study of the…
Based on very deep photometry, Surface Brightness Fluctuations (SBF) have been traditionally used to determine galaxy distances. We have recently computed SBF spectra of stellar populations at moderately high resolution, which are fully…
We develop a method to estimate photometric metallicities by simultaneously fitting the dereddened colors u-g, g-r, r-i and i-z from the SDSS with those predicted by the metallicity-dependent stellar loci. The method is tested with a…
The growing ``Hubble tension'' has prompted the need for precise measurements of cosmological distances. This paper demonstrates a purely geometric approach for determining the distance to extragalactic binaries through a joint analysis of…
Differences between the local value of the Hubble constant measured via the distance ladder versus the value inferred from the cosmic microwave background with the assumption of the standard $\Lambda$CDM model have reached over 5$\sigma$…
We studied blue horizontal branch stars (BHBs), and calculated their radial velocities. Spectra of these stars have been obtained with moderate signal-to-noise ratio for five blue horizontal-branch stars using the 2 meter telescope and…
We present some results of an observational and theoretical study on unresolved stellar systems based on the Surface Brightness Fluctuations (SBF) technique. It is shown that SBF magnitudes are a valuable tracer of stellar population…
Differences in clustering properties between galaxy subpopulations complicate the cosmological interpretation of the galaxy power spectrum, but can also provide insights about the physics underlying galaxy formation. To study the nature of…
We present an algorithm to photometrically calibrate wide field optical imaging surveys, that simultaneously solves for the calibration parameters and relative stellar fluxes using overlapping observations. The algorithm decouples the…
We present an in-depth study of surface brightness fluctuations (SBFs) in low-luminosity stellar systems. Using the MIST models, we compute theoretical predictions for absolute SBF magnitudes in the LSST, HST ACS/WFC, and proposed Roman…
We propose a novel means of directly measuring cosmological distances using scintillated microlensing of fast radio bursts (FRBs). In standard strong lensing measurements of cosmic expansion, the main source of systematic uncertainty lies…
I show that the standard microlensing technique to measure the angular radius of a star using color/surface-brightness relations can be inverted, via late-time proper motion measurements, to calibrate these relations. The method is…
We present the stellar density profile of the outer halo of the Galaxy traced over a range of Galactocentric radii from $15< R_{GC} < 220$ kpc by blue horizontal branch (BHB) stars. These stars are identified photometrically using deep…
We present the optical data for 195 HI-selected galaxies that fall within both the Sloan Digital Sky Survey (SDSS) and the Parkes Equatorial Survey (ES). The photometric quantities have been independently recomputed for our sample using a…
The number of stellar angular diameter measurements has greatly increased over the past few years due to innovations and developments in the field of long baseline optical interferometry (LBOI). We use a collection of high-precision angular…
Color Magnitude Diagrams (CMDs) of individual stars in 8 Globular Clusters in M31 down to about 1 mag fainter (V$\sim 26.5$) than the Horizontal Branch have been obtained with the Hubble Space Telescope. In particular, we observed G280 and…
The connection between mass loss on the red giant branch (RGB) and horizontal branch (HB) morphology in globular clusters (GCs) has long been acknowledged but the mechanisms governing mass loss remains poorly understood from a theoretical…
The Infrared Surface Brightness (IRSB) technique is a specific application of the Baade-Wesselink method. Given a proper calibration, well covered optical and near-infrared photometry, as well as radial velocity curves, it allows for…
We identified and characterized the largest (536) RR Lyrae (RRL) sample in a Milky Way dSph satellite (Sculptor) based on optical photometry data collected over $\sim$24 years. The RRLs display a spread in V-magnitude ($\sim$0.35 mag) which…
The purpose of this letter is to compare the quality of different methods for estimating stellar masses of galaxies. We compare the results of (a) fitting stellar population synthesis models to broad band colors from SDSS and 2MASS, (b) the…