Search Publications
One Thousand Days of SN2015bn: HST Imaging Shows a Light Curve Flattening Consistent with Magnetar Predictions
Berger, Edo; Chornock, Ryan; Alexander, Kate D. +9 more
We present the first observations of a Type I superluminous supernova (SLSN) at ≳1000 days after maximum light. We observed SN 2015bn using the Hubble Space Telescope (HST) Advanced Camera for Surveys in the F475W, F625W and F775W filters at 721 days and 1068 days. SN 2015bn is clearly detected and resolved from its compact host, allowing reliable…
3D Asymmetrical motions of the Galactic outer disc with LAMOST K giant stars
Deng, Licai; Carlin, Jeffrey L.; Wang, Haifeng +1 more
We present a three dimensional velocity analysis of Milky Way disc kinematics using LAMOST K giant stars and the GPS1 proper motion catalogue. We find that Galactic disc stars near the anticentre direction (in the range of Galactocentric distance between R = 8 and 13 kpc and vertical position between Z = -2 and 2 kpc) exhibit asymmetrical motions …
A Machine-learning-based Investigation of the Open Cluster M67
Gao, Xinhua
In this paper, we use a machine-learning method, random forest (RF), to identify reliable members of the old (4 Gyr) open cluster M67 based on the high-precision astrometry and photometry taken from the second Gaia data release (Gaia-DR2). The RF method is used to calculate membership probabilities of 71,117 stars within 2.°5 of the cluster center…
Onset of the Magnetic Explosion in Solar Polar Coronal X-Ray Jets
Panesar, Navdeep K.; Moore, Ronald L.; Sterling, Alphonse C.
We follow up on the Sterling et al. discovery that nearly all polar coronal X-ray jets are made by an explosive eruption of a closed magnetic field carrying a miniature filament in its core. In the same X-ray and EUV movies used by Sterling et al., we examine the onset and growth of the driving magnetic explosion in 15 of the 20 jets that they stu…
First constraints on the stellar mass function of star-forming clumps at the peak of cosmic star formation
Adamo, Angela; Dessauges-Zavadsky, Miroslava
Star-forming clumps dominate the rest-frame ultraviolet morphology of galaxies at the peak of cosmic star formation. If turbulence driven fragmentation is the mechanism responsible for their formation, we expect their stellar mass function to follow a power law of slope close to -2. We test this hypothesis performing the first analysis of the stel…
The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MegaSaura). II. Stacked Spectra
Dahle, H.; Rigby, J. R.; Bayliss, M. B. +8 more
We stack the rest-frame ultraviolet spectra of N = 14 highly magnified gravitationally lensed galaxies at redshifts 1.6< z< 3.6. The resulting new composite spans 900< {λ }{rest}< 3000 Å, with a peak signal-to-noise ratio (S/N) of 103 per spectral resolution element (∼100 km s-1). It is the highest S/N, highest sp…
Two Transient X-Ray Quasi-periodic Oscillations Separated by an Intermediate State in 1H 0707-495
Zhang, Peng; Zhang, Peng-fei; Yan, Jing-zhi +3 more
In the narrow-line Seyfert 1 galaxy 1H 0707-495, recently a transient quasi-periodic oscillation (QPO) signal with a frequency of ∼ 2.6× {10}-4 Hz has been detected at a high statistical significance. Here, we reanalyze the same set of XMM-Newton data observed on 2008 February 4 with the weighted-wavelet Z-transform method. In addition …
Dark passengers in stellar surveys
Zhu, Wei; Hotokezaka, Kenta; Beniamini, Paz +1 more
We develop stellar population models to predict the number of binaries with a single luminous member is Gaia and Hipparcos. Our models yield dozens of detections of black hole luminous companion (BHLC) binaries and hundreds to thousands of neutron star luminous companion (NSLC) binaries with Gaia. Interestingly, our models also yield a single dete…
Bayesian evidences for dark energy models in light of current observational data
Lonappan, Anto. I.; Kumar, Sumit; Ruchika +2 more
We do a comprehensive study of the Bayesian evidences for a large number of dark energy models using a combination of latest cosmological data from SNIa, CMB, BAO, strong lensing time delay, growth measurements, measurements of Hubble parameter at different redshifts and measurements of angular diameter distance by Megamaser Cosmology Project. We …
The Dusty Galactic Center as Seen by SCUBA-2
Tilanus, R. P. J.; Currie, M. J.; Chrysostomou, A. +9 more
We present new JCMT SCUBA-2 observations of the Galactic Center region from 355° < l< 5° and b< +/- 1° , covering 10 × 2 square degrees along the Galactic Plane to a depth of 43 mJy beam-1 at 850 µm and 360 mJy beam-1 at 450 µm. We describe the mapping strategy and reduction method used. We present 1…