Search Publications
Discovery of Tidal Tails around the Old Open Cluster NGC 2506
Gao, Xinhua
We report the discovery of tidal tails around the old open cluster NGC 2506 based on Gaia-DR2. A principal-component analysis and Gaussian mixture model are used to identify extra-tidal stars. We identify 2301 stars closely related to the cluster, 147 of which are likely extra-tidal stars. We find clear evidence for the existence of two well-defin…
When the disc's away, the stars will play: dynamical masses in the nova-like variable KR Aur with a pinch of accretion
Gänsicke, B. T.; Koester, D.; Toloza, O. +8 more
We obtained time-resolved optical photometry and spectroscopy of the nova-like variable KR Aurigae in the low state. The spectrum reveals a DAB white dwarf (WD) and a mid-M dwarf companion. Using the companion star's i-band ellipsoidal modulation we refine the binary orbital period to be P = 3.906519 ± 0.000001 h. The light curve and the spectra s…
Eclipsing Binaries in the Open Cluster Ruprecht 147. III. The Triple System EPIC 219552514 at the Main-sequence Turnoff
Torres, Guillermo; Vanderburg, Andrew; Rizzuto, Aaron C. +3 more
Spectroscopic observations are reported for the 2.75 day, double-lined, detached eclipsing binary EPIC 219552514 located at the turnoff of the old nearby open cluster Ruprecht 147. A joint analysis of our radial-velocity measurements and the K2 light curve leads to masses of ${M}_{1}={1.509}_{-0.056}^{+0.063}\,{M}_{\odot }$ and ${M}_{2}={0.649}_{-…
Water megamaser emission in hard X-ray selected AGN
Ubertini, P.; Malizia, A.; Bassani, L. +4 more
Context. Water megamaser emission at 22 GHz has proven to be a powerful tool for astrophysical studies of active galactic nuclei (AGN) because it allows an accurate determination of the mass of the central black hole and of the accretion disc geometry and dynamics. However, after searches among thousands of galaxies, only about 200 of them have sh…
OGLE-ing the Magellanic System: Cepheids in the Bridge
Udalski, Andrzej; Mróz, Przemek; Szymański, Michał K. +12 more
We present a detailed analysis of the Magellanic Bridge Cepheid sample constructed using the Optical Gravitational Lensing Experiment Collection of Variable Stars. Our updated Bridge sample contains 10 classical and 13 anomalous Cepheids. We calculate their individual distances using optical period-Wesenheit relations and construct three-dimension…
Measuring the Heating and Cooling of the Interstellar Medium at High Redshift: PAH and [C II] Observations of the Same Star-forming Galaxies at z ∼ 2
Kirkpatrick, Allison; Dickinson, Mark E.; McKinney, Jed +4 more
Star formation depends critically on cooling mechanisms in the interstellar medium (ISM); however, thermal properties of gas in galaxies at the peak epoch of star formation (z ∼ 2) remain poorly understood. A limiting factor in understanding the multiphase ISM is the lack of multiple tracers detected in the same galaxies, such as Polycyclic Aromat…
On the Absence of High-redshift AGNs: Little Growth in the Supermassive Black Hole Population at High Redshifts
Bauer, F. E.; Barger, A. J.; Cowie, L. L. +1 more
We search for high-redshift (z > 4.5) X-ray active galactic nuclei (AGNs) in the deep central (off-axis angle < 5'7) region of the 7 Ms Chandra Deep Field-South X-ray image. We compile an initial candidate sample from direct X-ray detections. We then probe more deeply in the X-ray data by using preselected samples with high spatial resolutio…
HATS-47b, HATS-48Ab, HATS-49b, and HATS-72b: Four Warm Giant Planets Transiting K Dwarfs
Latham, David W.; Jordán, Andrés; Butler, R. P. +43 more
We report the discovery of four transiting giant planets around K dwarfs. The planets HATS-47b, HATS-48Ab, HATS-49b, and HATS-72b have masses of ${0.369}_{-0.021}^{+0.031} ${M}_{{\rm{J}}}, ${0.243}_{-0.030}^{+0.022} ${M}_{{\rm{J}}}, ${0.353}_{-0.027}^{+0.038} ${M}_{{\rm{J}}}, and $0.1254\pm 0.0039 ${M}_{{\rm{J}}}, respectively, and radii of $1.117…
Robust diffraction-limited near-infrared-to-near-ultraviolet wide-field imaging from stratospheric balloon-borne platforms—Super-pressure Balloon-borne Imaging Telescope performance
Jauzac, Mathilde; Tam, Sut-Ieng; Benton, Steven J. +26 more
At a fraction of the total cost of an equivalent orbital mission, scientific balloon-borne platforms, operating above 99.7% of the Earth's atmosphere, offer attractive, competitive, and effective observational capabilities—namely, space-like seeing, transmission, and backgrounds—which are well suited for modern astronomy and cosmology. The Super-p…
A Magnetic White Dwarf Accretion Model for the Anomalous X-Ray Pulsar 4U 0142+61
Rodrigues, Claudia V.; Coelho, Jaziel G.; Castro, Manuel +2 more
The quiescent emission of the anomalous X-ray pulsar (AXP) 4U 0142+61 extends over a broad range of energy, from radio up to hard X-rays. In particular, this object is unique among soft gamma-ray repeaters (SGRs) and AXPs in presenting simultaneously mid-infrared emission and pulsed optical emission. In spite of the many propositions to explain th…