相关论文: A supernova distance to the anchor galaxy NGC 4258
NGC 4258 is a critical galaxy for establishing the extragalactic distance scale and estimating the Hubble constant (Ho). Water masers in the nucleus of the galaxy orbit about its supermassive black hole, and very long baseline…
We report a new geometric maser distance estimate to the active galaxy NGC 4258. The data for the new model are maser line-of-sight velocities and sky positions from 18 epochs of Very Long Baseline Interferometry observations, and…
Type II-plateau supernovae (SNe II-P) are the classic variety of core-collapse events that result from isolated, massive stars with thick hydrogen envelopes intact at the time of explosion. Their distances are now routinely estimated…
In a previous paper (Maoz et al. 1999), we reported a Hubble Space Telescope (HST) Cepheid distance to the galaxy NGC 4258 obtained using the calibrations and methods then standard for the Key Project on the Extragalactic Distance Scale.…
We present a reanalysis of the water maser system in NGC 4258 to reassess its geometric distance, commonly reported as approximately 7.6 Mpc with percent-level accuracy, a key anchor in extragalactic distance ladder calibrations and recent…
We present initial results from a time-series BVI survey of two fields in NGC 4258 using the Advanced Camera for Surveys onboard the Hubble Space Telescope. This galaxy was selected because of its accurate maser-based distance, which is…
In a recent paper describing HST observations of Cepheids in the spiral galaxy NGC 4258, Newman et al. (2001) report that the revised calibrations and methods for the Key Project on the Extragalactic Distance Scale yield that the true…
{Supernova (SN) siblings are powerful tools used to calibrate and improve distance measurement methods, and to make the systematic uncertainty to distances to their host galaxies considerably lower compared to other techniques.} {In this…
Distance to the Whirlpool Galaxy (M51, NGC 5194) is estimated using published photometry and spectroscopy of the Type II-P supernova SN 2005cs. Both the Expanding Photosphere Method (EPM) and the Standard Candle Method (SCM), suitable for…
I use the largest available sample of Type II plateau supernovae to examine the previously reported luminosity-velocity relation. This study confirms such relation which permits one to standardize the luminosities of these objects from a…
In the nearby galaxy NGC 4258, the well-modeled orbital motion of H$_2$O masers about its supermassive black hole provides the means to measure a precise geometric distance. As a result, NGC 4258 is one of a few "geometric anchors"…
CCD-photometry and low-resolution spectroscopy of the bright supernova SN 2000E in NGC 6951 are presented. Both the light curve extending up to 150 days past maximum and the spectra obtained at 1 month past maximum confirm that SN 2000E is…
Distances measured using Cepheid variable stars have been essential for establishing the cosmological distance scale and the value of the Hubble constant. These stars have remained the primary extragalactic distance indicator since 1929…
We accurately determine a new Cepheid distance to M101 (NGC 5457) using archival HST/ACS V and I time series photometry of two fields within the galaxy. We make a slight modification to the ISIS image subtraction package to obtain optimal…
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)…
The calibration of the Type Ia supernova distances using HST observations of Cepheid variables is discussed. A new maximum likelihood method of calibration is applied to derive the PL relation for a composite sample of Cepheids in the LMC…
We derive a distance of $15.8\pm0.4$ Mpc to the archetypical Seyfert 1 galaxy NGC 4151 based on the near-infrared Cepheid Period-Luminosity relation and new Hubble Space Telescope multiband imaging. This distance determination, based on…
We present results of a ground-based survey for Cepheid variables in NGC 4258. This galaxy plays a key role in the Extragalactic Distance Scale due to its very precise and accurate distance determination via VLBI observations of water…
In this paper we review the various high precision methods that are now available to determine the distance to NGC 5128. These methods include: Cepheids, TRGB (tip of the red giant branch), PNLF (planetary nebula luminosity function), SBF…
We investigate the use of type Ic Super Luminous Supernovae as standardizable candles and distance indicators. Their appeal as cosmological probes stems from their remarkable peak luminosities, hot blackbody temperatures and bright…