Search Publications
Spectroscopically Identified Cataclysmic Variables from the LAMOST Survey. I. The Sample
Qin, Li; Hou, Wen; Li, Yin-Bi +1 more
A sample of cataclysmic variables (CVs) is presented including spectroscopically identified 380 spectra of 245 objects, of which 58 CV candidates are new discoveries. The BaggingTopPush and the Random Forest algorithms are applied to the Fifth Data Release (DR5) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to retrieve …
Revised astrometric calibration of the Gemini Planet Imager
Duchêne, Gaspard; Esposito, Thomas M.; Oppenheimer, Rebecca +49 more
We present a revision to the astrometric calibration of the Gemini Planet Imager (GPI), an instrument designed to achieve the high contrast at small angular separations necessary to image substellar and planetary-mass companions around nearby, young stars. We identified several issues with the GPI data reduction pipeline (DRP) that significantly a…
On a century of extragalactic novae and the rise of the rapid recurrent novae
Darnley, Matthew J.; Henze, Martin
Novae are the observable outcome of a transient thermonuclear runaway on the surface of an accreting white dwarf in a close binary system. Their high peak luminosity renders them visible in galaxies out beyond the distance of the Virgo Cluster. Over the past century, surveys of extragalactic novae, particularly within the nearby Andromeda Galaxy, …
Model-independent Estimations for the Cosmic Curvature from the Latest Strong Gravitational Lensing Systems
Li, Zhengxiang; Zhou, Huan
Model-independent measurements for the cosmic spatial curvature, which is related to the nature of cosmic spacetime geometry, play an important role in cosmology. On the basis of the distance sum rule in the Friedmann-Lemaître-Robertson-Walker metric, (distance ratio) measurements of strong gravitational lensing (SGL) systems, together with distan…
Monitoring the Spatio-temporal Evolution of a Reconnection X-line in Space
Vaivads, A.; Wang, Z.; Cao, J. B. +3 more
Inherently, magnetic reconnection—the process responsible for stellar flares and magnetospheric substorms—is very dynamic in space, owing to magnetic fluctuations and unsteady inflows. However, this process was always explained as a static picture in spacecraft measurements, neglecting the temporal evolution. This picture is not correct. Here we p…
Discovery of a mid-infrared protostellar outburst of exceptional amplitude
Minniti, D.; Stecklum, B.; Saito, R. K. +12 more
We report the discovery of a mid-infrared outburst in a young stellar object (YSO) with an amplitude close to 8 mag at λ ≈ 4.6 µm. WISEA J142238.82-611553.7 is one of 23 highly variable Wide-field Infrared Survey Explorer (WISE) sources discovered in a search of infrared dark clouds (IRDCs). It lies within the small IRDC G313.671-0.309 (d ≈2…
Sun-as-a-star Spectral Irradiance Observations of Transiting Active Regions
Toriumi, Shin; Cheung, Mark C. M.; DeRosa, Marc L. +3 more
Major solar flares are prone to occur in active-region (AR) atmospheres associated with large, complex, dynamically evolving sunspots. This points to the importance of monitoring the evolution of starspots, not only in visible but also in ultraviolet (UV) and X-rays, in understanding the origin and occurrence of stellar flares. To this end, we per…
Galactic extinction laws - I. A global NIR analysis with 2MASS photometry
García-Lario, P.; Maíz Apellániz, J.; Barbá, R. H. +2 more
We have started an ambitious program to determine if the full diversity of extinction laws is real or if some of it is due to calibration or methodological issues. Here we start by analysing the information on near-infrared (NIR) extinction in a Two Micron All-Sky Survey (2MASS) stellar sample with good quality photometry and very red colours. We …
Optical to Near-infrared Transmission Spectrum of the Warm Sub-Saturn HAT-P-12b
Deming, Drake; Nikolov, Nikolay; Sing, David K. +12 more
We present the transmission spectrum of HAT-P-12b through a joint analysis of data obtained from the Hubble Space Telescope Space Telescope Imaging Spectrograph and Wide Field Camera 3 and Spitzer, covering the wavelength range 0.3-5.0 µm. We detect a muted water vapor absorption feature at 1.4 µm attenuated by clouds, as well as a Ray…
A search for the origin of the interstellar comet 2I/Borisov
Bailer-Jones, Coryn A. L.; Meech, Karen J.; Ye, Quanzhi +2 more
The discovery of the second interstellar object 2I/Borisov on 2019 August 30 raises the question of whether it was ejected recently from a nearby stellar system. Here we compute the asymptotic incoming trajectory of 2I/Borisov, based on both recent and pre-discovery data extending back to December 2018, using a range of force models that account f…