Related papers: HST Fine Guidance Sensor Parallaxes for Four Class…
There are 88 stars which lack colours, but have measured parallaxes in \textit{Gaia} EDR3 that place them within 20\,pc from the sun. Among them we found two new common parallax and proper motion (CPPM) companions separated from their…
We present redshifts for 115 emission line objects in the Hubble Ultra Deep Field (HUDF) identified through the GRism ACS Program for Extragalactic Science (GRAPES) project using the slitless grism spectroscopy mode of the ACS Camera on the…
We present a kinematical study of the optical ejecta of GK Per. It is based on proper motions measurements of 282 knots from ~20 images spanning 25 years. Doppler-shifts are also computed for 217 knots. The combination of proper motions and…
Strong gravitational lensing by massive galaxy clusters offers rare opportunities to observe multiple images of distant ($z \gtrsim 2$) Type Ia supernovae (SNe) and to resolve the properties of their host galaxies. A recent outstanding…
(abridged)Multiple systems for which the astrometric and spectroscopic orbit are known offer the unique possibility of determining the distance to these systems directly without any assumptions. They are therefore ideal objects for a…
In this study, we used geometric distances at high redshifts (both luminosity and angular) to perform a cosmographic analysis with the Pad\'e method, which stabilizes the behaviour of the cosmographic series in this redshift regime.…
The origin and calibration of the maximum absolute magnitude relation with decline time (MMRD) for novae, first derived by Zwicky (1936) empirically validated by McLaughlin (1940) and widely used to estimate distances to classical novae and…
Utilising the unique location of red clump giants on colour-magnitude diagrams obtained from various near-IR surveys, we derived specific reddening-distance relations towards 119 Galactic novae for which independent reddening measurements…
We present optical and near-infrared (NIR, $YJH$-band) observations of 42 Type Ia supernovae (SNe Ia) discovered by the untargeted intermediate Palomar Transient Factory (iPTF) survey. This new data-set covers a broad range of redshifts and…
Monitoring the long-term radial velocity (RV) and acceleration of nearby stars has proven an effective method for directly detecting binary and substellar companions. Some fraction of nearby RV trend systems are expected to be comprised of…
We analyse Gaia EDR3 parallax systematics as a function of magnitude and sky location using a recently published catalogue of 12,500 asteroseismic red-giant star distances. We selected ~ 3500 red clump (RC) stars of similar chemical…
The installation of the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) will revolutionize the study of high-redshift galaxy populations. Initial observations of the HST Ultra Deep Field (UDF) have yielded multiple z>~7…
Using only Ia supernova (SN) observations, it is not possible to distinguish the evolution of the SN absolute magnitude $M_B$ from an arbitrary evolution of the Hubble parameter H(z). However, using Etherington's distance-duality relation,…
We present the direct imaging detection of a faint tertiary companion to the single-lined spectroscopic binary HD 8375 AB. Initially noticed as an 53 m/s/yr Doppler acceleration by Bowler et al. 2010, we have obtained high-contrast adaptive…
We present the first results of a photometric survey of poorly studied nova remnants in the Northern Hemisphere. The main results are as follows: DM Gem shows a modulation at 0.123 d (probably linked to the orbit) and rapid variations at…
Some transients, although classified as novae based on their maximum and early decline optical spectra, cast doubts on their true nature and whether nova impostors might exist. We monitored a candidate nova which displayed a distinctly…
We aim to identify new intermediate polars (IPs) in XMM-Newton observations from a list of promising candidates. By selecting targets not previously known to be X-ray bright we aim to uncover evidence for an X-ray underluminous IP…
We have coordinated Hubble Space Telescope photometry with ground-based discovery for three supernovae: two SN Ia near z~0.5 (SN 1997ce, SN 1997cj) and a third event at z=0.97 (SN 1997ck). The superb spatial resolution of HST separates each…
We present radio observations (1--40 GHz) for 36 classical novae, representing data from over five decades compiled from the literature, telescope archives, and our own programs. Our targets display a striking diversity in their optical…
We inform on the progress of our on-going project to identify and classify old classical novae, using deep UBVR photometry and subsequent spectroscopy for a proper candidate confirmation, and time-resolved observations in order to find the…