Related papers: HST Fine Guidance Sensor Parallaxes for Four Class…

We examine the prospects for measurement of the Hubble parameter $H_0$ via observation of the secular parallax of other galaxies due to our own motion relative to the cosmic microwave background rest frame. Peculiar velocities make distance…

We reconsider calibration of statistical distance scales for planetary nebulae, examining precision and systematic error for various distance methods used as well as the scales themselves. A different calibration strategy, one based on…

We combine Hubble Space Telescope (HST) Fine Guidance Sensor, Hipparcos, and Gaia DR3 astrometric observations of the K0 V star 14 Her with the results of an analysis of extensive ground-based radial velocity data to determine perturbation…

We present photometry of 30 Galactic RR Lyrae variables taken with HST WFC3/IR for the Carnegie-Chicago Hubble Program. These measurements form the base of the distance ladder measurements that comprise a pure Population II base to a…

{We combine the results of our earlier study of the UV characteristics of 18 classical novae (CNe) with data from the literature and with the recent precise distance determinations from the Gaia satellite to investigate the statistical…

Determining reliable distances to classical novae is a challenging but crucial step in deriving their ejected masses and explosion energetics. Here we combine radio expansion measurements from the Karl G. Jansky Very Large Array with…

We report results of an HST "snapshot" survey aimed at finding resolved binary companions of the central stars of Galactic planetary nebulae (PNe). Using WF/PC and WFPC2, we searched the fields of 113 PNe for stars whose close proximity to…

We present a measurement of the Hubble constant ($H_0$) using type Ia supernova (SNe Ia) in the near-infrared (NIR) from the recently updated sample of SNe Ia in nearby galaxies with distances measured via Cepheid period-luminosity…

Trigonometric parallax observations made with the Hubble Space Telescope's Fine Guidance Sensor #3 (HST FGS) of seven Hyades Cluster members in six fields of view have been analyzed along with their proper motions to determine the distance…

We sing the praises of the central limit theorem. Having previously removed all other possible causes of significant systematic error in the statistical parallax determination of RR Lyrae absolute magnitudes, we investigate systematic…

We present an analysis of the Hubble diagram for 12 Type Ia supernovae (SNe Ia) observed in the near-infrared J and H bands. We select SNe exclusively from the redshift range 0.03 < z < 0.09 to reduce uncertainties coming from peculiar…

Strong lensing time delay measurement is a promising method to address the Hubble tension, offering a completely independent approach compared to both the cosmic microwave background analysis and the local distance ladder. As a third-party…

The rising phase toward the optical maximum of a classical nova is one of the last frontiers of nova study. Constructing free-free emission model light curves based on our fully self-consistent nova explosion models, we present several…

Quadruple gravitational lens systems offer the possibility of measuring time delays for image pairs, microlensing effects, and extinction in distant galaxies. Observations of these systems may be used to obtain estimates of H_o and to study…

We present the discovery of a Type Ia supernova (SN) at redshift $z = 1.914$ from the CANDELS multi-cycle treasury program on the \textit{Hubble Space Telescope (HST)}. This SN was discovered in the infrared using the Wide-Field Camera 3,…

The 'extreme Population A (xA) quasars' approaching, sometimes exceeding the Eddington limit, are a type of quasars that could serve as a standard candle to measure distances too large for supernovae type Ia (SNe Ia) to be observable. For…

Supernova H0pe is a multiply-imaged Type Ia supernova (SN~Ia) and the second lensed SN to yield a measurement of the Hubble constant by the time-delay cosmography method, finding $H_0 = 75.4^{+8.1}_{-5.5} \text{km s}^{-1} \text{Mpc}^{-1}$…

We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an…

We propose a method to identify quasars radiating closest to the Eddington limit, defining primary and secondary selection criteria in the optical, UV and X-ray spectral range based on the 4D eigenvector 1 formalism. We then show that it is…

The good energy resolution (3--4 keV FWHM) of the Transient Gamma Ray Spectrometer (TGRS) on board the WIND spacecraft makes it sensitive to Doppler-shifted outbursts of 511 keV electron-positron annihilation radiation, the reason being…