Related papers: A New Cepheid Distance Measurement and Method for …
Using a slitless spectroscopy method with the 8.2 m Subaru telescope and its FOCAS Cassegrain spectrograph, we have increased the number of planetary nebula (PN) detections and PN velocity measurements in the flattened elliptical galaxy NGC…
Several standard candles have been tested and used to measure accurate extragalactic distances over the past decades. There have been discussions regarding the possibility of using Type-II Cepheids (T2Cs) as an alternative tool, but rarely…
We report the discovery of a periodic modulation in the optical lightcurve of the candidate ultra-compact X-ray binary 4U1822-000. Using time-resolved optical photometry taken with the William Herschel Telescope we find evidence for a…
Classical Cepheids provide the foundation for the empirical extragalactic distance ladder. Milky Way Cepheids are the only stars in this class accessible to trigonometric parallax measurements. However, the parallaxes of Cepheids from the…
We employ a new way to measure the distance to NGC1052-DF2 via internal stellar velocity dispersions ($\sigma$) of its globular clusters (GCs). We obtained deep (15.1h), R=18,200, Ca Triplet integrated-light spectra for 10 GCs in…
We employ the very recent photometric data of the OGLE project together with stellar atmosphere and linear pulsation models to determine the distance modulus of the Small Magellanic Cloud from its double-mode Cepheids. Based on the…
Repeated imaging observations have been made of NGC 4527 with the Hubble Space Telescope between April and June 1999, over an interval of 69 days. Images were obtained on 12 epochs in the F555W band and on five epochs in the F814W band. The…
Recent determination of the Hubble constant via Cepheid-calibrated supernovae by \citet{riess_2.4_2016} (R16) find $\sim 3\sigma$ tension with inferences based on cosmic microwave background temperature and polarization measurements from…
We present Period-Luminosity Relations (PLRs) for 55 Cepheids in M31 with periods ranging from 4 to 78 days observed with the Hubble Space Telescope (HST) using the same three-band photometric system recently used to calibrate their…
Gravitational lensing by galaxy clusters can create extreme magnification near the cluster caustics, thereby enabling detection of individual luminous stars in high-redshift background galaxies. Those stars can include non-explosive…
We present a differential study of 500 Magellanic Cepheids with 3 million measurements obtained as a by-product of the EROS microlensing survey. The data-set is unbiased and provides an excellent basis for a differential analysis between…
We present accurate and deep multi-band ($g,r,i$) photometry of the Local Group dwarf irregular galaxy NGC 6822. The images were collected with wide field cameras at 2m/4m- (INT,CTIO,CFHT) and 8m-class telescopes (SUBARU) covering a 2…
Evidence is presented which supports findings that the classical Cepheid VIc period-Wesenheit function is relatively insensitive to metallicity. The viability of a recently advocated strong metallicity dependence was evaluated by applying…
We use the Expanding Photosphere Method to determine distances to 10 type II supernovae. The effects of asymmetries, extinction, and flux dilution are explored. Using empirical evidence and time-independent, spherical models which treat H…
We used early time photometry and spectroscopy of 12 Type II plateau Supernovae (SNe IIP) to derive their distances using the Expanding Photosphere Method (EPM). We performed this study using two sets of Type II supernovae (SNe II)…
We characterize the star formation in the low-metallicity galaxy NGC 6822 over the past few hundred million years, using GALEX far-UV (FUV, 1344-1786 A) and near-UV (NUV, 1771-2831 A) imaging, and ground-based Ha imaging. From GALEX FUV…
We have identified 82 short-period variable stars in Sextans A from deep WFPC2 observations. All of the periodic variables appear to be short-period Cepheids, with periods as small as 0.8 days for fundamental-mode Cepheids and 0.5 days for…
We have obtained deep near infrared J- and K-band observations of 14 BL Herculis and 5 W Virginis SMC stars from the OGLE III survey with the ESO New Technology Telescope equipped with the SOFI infrared camera. From these observations,…
We present the results of a search for HI 21-cm line emission from the circumstellar environments of four Galactic Cepheids (RS Pup, X Cyg, $\zeta$ Gem, and T Mon) based on observations with the Karl G. Jansky Very Large Array. The…
The DIRECT project aims to determine direct distances to two important galaxies in the cosmological distance ladder - M31 and M33 - using detached eclipsing binaries (DEBs) and Cepheids. We present the results of the first large-scale…