Search Publications
Role of the companion lensing galaxy in the CLASS gravitational lens B1152+199
Zhang, L.; Zhang, M.; Yuan, Q. +1 more
We reinvestigate the Cosmic Lens All-Sky Survey (CLASS) gravitational lens B1152+199 using archived Hubble Space Telescope (HST) data and Very Long Baseline Interferometry (VLBI) data. A consistent luminosity ratio within effective radius between the host galaxy and the X-galaxy is measured from HST tri-band images, which leads to a mass ratio bet…
OGLE-BLG504.12.201843: a possible extreme dwarf nova
Strader, Jay; Udalski, Andrzej; Prieto, Jose L. +5 more
We present the analysis of existing optical photometry and new optical spectroscopy of the candidate cataclysmic variable star OGLE-BLG504.12.201843. As was shown previously, this object has an orbital period of 0.523419 d and exhibits year-long outbursts with a mean period of 973 d. Using digitized photographic archives, we show that the earliest…
Characterization of the eclipsing post-common-envelope binary TIC 60040774
Knigge, C.; Scaringi, S.; Buckley, D. A. H. +2 more
Binaries with a white dwarf primary and a main sequence secondary can be used to test our understanding of both single and binary star evolution. A small fraction of such systems experienced a common-envelope phase from which they emerged with a relatively short orbital period. Here, we present the characterization of an eclipsing post-common-enve…
Search for gamma-ray emission from a galactic supernova with the anticoincidence system of SPI
Jean, P.; Isern, J.; Bravo, E. +1 more
The detection of the very early gamma-emission of a Type Ia supernova (SNIa) could provide a deep insight on the explosion mechanism and nature of the progenitor. However, this has not been yet possible as a consequence of the expected low luminosity and the distance at which all the events have occurred up to now. An SNIa occurring in our Galaxy …
The OmegaWhite survey for short-period variable stars - VI. Open clusters
Groot, P. J.; Ramsay, G.; Jeffery, C. S. +3 more
Using light curves with ~3 min cadence and a duration of 2 h made using the OmegaWhite survey, we present the results of a search for short-period variable stars in the field of 20 open clusters. We identified 92 variable stars in these fields. Using a range of cluster member catalogues and Gaia EDR3 data, we have determined that 10 are cluster me…
Chemical composition of a palomar 12 blue straggler
Pasquini, L.; Bonifacio, P.; Randich, S. +5 more
With the equivalent area of a 16-m telescope, ESPRESSO in 4UT mode allows to inaugurate high resolution spectroscopy for solar-type stars belonging to extragalactic globular clusters. We determine the chemical composition of an extragalactic blue straggler (BS). The star has a G magnitude of 19.01 and belongs to the globular cluster Pal12, that is…
The orbital architecture and stability of the µ Arae planetary system
Goździewski, K.
We re-analyse the global orbital architecture and dynamical stability of the HD 160691 planetary system. We have updated the best-fitting elements and minimal masses of the planets based on literature precision radial velocity (RV) measurements, now spanning 17.3 yr. This is twice the RVs interval used for the first characterization of the system …
UGPS J194310+183851: an unusual optical and X-ray faint cataclysmic variable?
Maccarone, T. J.; Cooper, W. J.; Lucas, P. W. +7 more
The growing number of multi-epoch optical and infrared sky surveys are uncovering unprecedented numbers of new variable stars, of an increasing number of types. The short interval between observations in adjacent near-infrared filters in the UKIDSS Galactic Plane Survey (UGPS) allows for the discovery of variability on the time-scale of minutes. W…
Constraining the shape of Milky Way satellites with distance gradients
Koposov, Sergey E.; An, Zhaozhou
We combine the Dark Energy Camera Legacy Survey DR8 photometry with Gaia photometry to study the 3D structure of Bootes I, Draco, Ursa Minor, Sextans, and Sculptor dwarf galaxies using blue horizontal branch (BHB) stars as distance indicators. We construct a new colour-absolute magnitude of BHB stars that we use to measure the distance gradients w…
X-ray absorption and reprocessing in the z 2.5 lensed quasar 2MASS J1042+1641
Stern, D.; Brightman, M.; Walton, D. J. +2 more
We present new broad-band X-ray observations of the z ~ 2.5 lensed quasar 2MASS J1042+1641, combining XMM-Newton, Chandra, and NuSTAR to provide coverage of the X-ray spectrum over the 0.3-40 keV bandpass in the observed frame, corresponding to the ~1-140 keV band in the rest frame of 2MASS J1042+1641. The X-ray data show clear evidence for strong…