Search Publications
X-Ray Spectral Properties of Seyfert I Galaxy LEDA 168563
Fabian, Andrew C.; Tsuruta, Sachiko; Liebmann, Andrew C. +2 more
Interesting among possible mechanisms responsible for X-ray emission from active galactic nuclei (AGNs) is ionized relativistic reflection (IRR). Since it arises close to the central black hole it can test strong gravity. Its characteristic features include a high energy Compton hump, a broad Fe Kα line, and a soft excess. Therefore, using the Swi…
Dating the Tidal Disruption of Globular Clusters with GAIA Data on Their Stellar Streams
Loeb, Abraham; Bose, Sownak; Ginsburg, Idan
The Gaia mission promises to deliver precision astrometry at an unprecedented level, heralding a new era for discerning the kinematic and spatial coordinates of stars in our Galaxy. Here, we present a new technique for estimating the age of tidally disrupted globular cluster streams using the proper motions and parallaxes of tracer stars. We evolv…
Investigating the Relation between Sunspots and Umbral Dots
Mathew, Shibu K.; Louis, Rohan E.; Yadav, Rahul
Umbral dots (UDs) are transient, bright features observed in the umbral region of a sunspot. We study the physical properties of UDs observed in sunspots of different sizes. The aim of our study is to relate the physical properties of UDs with the large-scale properties of sunspots. For this purpose, we analyze high-resolution G-band images of 42 …
Investigation of the High-energy Emission from the Magnetar-like Pulsar PSR J1119-6127 after the 2016 Outburst
Hu, Chin-Ping; Kong, A. K. H.; Hui, C. Y. +7 more
PSR J1119-6127 is a radio pulsar that behaved with magnetar-like bursts, and we performed a comprehensive investigation of this pulsar using the archival high-energy observations obtained after its outburst in 2016 July. After the 2016 outburst, specific regions on the neutron star (NS) surface were heated up to >0.3 and >1 keV from ∼0.2 keV…
Reconciling the Predictions of Microlensing Analysis with Radial Velocity Measurements for OGLE-2011-BLG-0417
Boisse, I.; Bachelet, E.; Street, R. A. +2 more
Microlensing is able to reveal multiple body systems located several kilo-parsec away from the Earth. Since it does not require the measurement of light from the lens, microlensing is sensitive to a range of objects, from free-floating planets to stellar black holes. But, if the lens emits enough light, the microlensing model predictions can be te…
Herschel and ALMA Observations of Massive SZE-selected Clusters
Hilton, Matt; Sifón, Cristóbal; Devlin, Mark J. +6 more
We present new Herschel observations of four massive, Sunyaev-Zel’dovich effect-selected clusters at 0.3≤slant z≤slant 1.1, two of which have also been observed with the Atacama Large Millimeter/submillimeter Array (ALMA). We detect 19 Herschel/Photoconductor Array Camera and Spectrometer (PACS) counterparts to spectroscopically confirmed cluster …
The Time Evolution of the HH 1 Jet Modeled as a Variable Outflow
Raga, A. C.; Castellanos-Ramírez, A.; Rodríguez-González, A.
The HH 1 jet is a chain of knots extending out to ∼20″ from the VLA 1 source of the HH 1/2 system. Four epochs of [S II] images obtained with the Hubble Space Telescope over a ∼20 yr period show that these knots have a time-evolving intensity as they travel away from the outflow source. We present an axisymmetric, gas-dynamic simulation of a two-s…
Stellar Mass and 3.4 µm M/L Ratio Evolution of Brightest Cluster Galaxies in COSMOS since z ∼ 1.0
Kartaltepe, Jeyhan S.; O'Dea, Christopher P.; Moustakas, John +3 more
We investigate the evolution of star formation rates (SFRs), stellar masses, and M/L 3.4 µm ratios of brightest cluster galaxies (BCGs) in the COSMOS survey since z ∼ 1 to determine the contribution of star formation to the growth-rate of BCG stellar mass over time. Through the spectral energy density (SED) fitting of the GALEX, C…
The Isophotal Structure of Star-forming Galaxies at 0.5 < z < 1.8 in CANDELS: Implications for the Evolution of Galaxy Structure
Barro, Guillermo; Hathi, Nimish P.; Koekemoer, Anton M. +15 more
We have measured the radial profiles of isophotal ellipticity (ɛ) and disky/boxy parameter A 4 out to radii of about three times the semimajor axes for ∼4600 star-forming galaxies (SFGs) between redshift 0.5 and 1.8 in the CANDELS/GOODS-S and UDS fields. Based on the average size-mass relation in each redshift bin, we divide our galaxie…
Polycyclic Aromatic Hydrocarbon Emission Toward the Galactic Bulge
Blommaert, J. A. D. L.; Peeters, E.; Cami, J. +1 more
We examine polycyclic aromatic hydrocarbon (PAH), dust, and atomic/molecular emission toward the Galactic bulge using Spitzer Space Telescope observations of four fields: C32, C35, OGLE, and NGC 6522. These fields are approximately centered on (l, b) = (0.°0, 1.°0), (0.°0, -1.°0), (0.°4, -2.°4), and (1.°0, -3.°8), respectively. Far-infrared photom…