Search Publications
First INTEGRAL Observations of V404 Cygni during the 2015 Outburst: Spectral Behavior in the 20-650 keV Energy Range
Ubertini, Pietro; Bazzano, Angela; Jourdain, Elisabeth +3 more
In 2015 June, the source V404 Cygni (= GS2023+38) underwent an extraordinary outburst. We present the results obtained during the first revolution dedicated to this target by the INTEGRAL mission and focus on the spectral behavior in the hard X-ray domain, using both SPI and IBIS instruments. The source exhibits extreme variability and reaches flu…
Propagating Disturbances in the Solar Corona and Spicular Connection
Pant, Vaibhav; Banerjee, Dipankar; Samanta, Tanmoy
Spicules are small, hairy-like structures seen at the solar limb, mainly at chromospheric and transition region lines. They generally live for 3-10 minutes. We study these spicules in a south polar region of the Sun with coordinated observations using the Interface Region Imaging Spectrograph (IRIS) and the Atmospheric Imaging Assembly (AIA) instr…
Episodic Ejection from Active Asteroid 311P/PANSTARRS
Mutchler, Max; Jewitt, David; Agarwal, Jessica +2 more
We examine the development of the active asteroid 311P/PANSTARRS (formerly, 2013 P5) in the period from 2013 September to 2014 February using high resolution images from the Hubble Space Telescope. This multi-tailed object is characterized by a single, reddish nucleus of absolute magnitude H >= 18.98 ± 0.10, corresponding to an equal-area spher…
XMM-Newton Observations of SGR 1806-20 Over Seven Years Following the 2004 Giant Flare
Kouveliotou, C.; Kaspi, V. M.; Younes, G.
We report on the study of 14 XMM-Newton observations of the magnetar SGR 1806-20 spread over a period of 8 years, starting in 2003 and extending to 2011. We find that in mid 2005, a year and a half after a giant flare (GF), the torques on the star increased to the largest value yet seen, with a long term average rate between 2005 and 2011 of | \do…
Using FUV to IR Variability to Probe the Star-Disk Connection in the Transitional Disk of GM Aur
Sitko, Michael; Calvet, Nuria; Ingleby, Laura +3 more
We analyze three epochs of ultraviolet, optical, and near-infrared (NIR) observations of the Taurus transitional disk GM Aur using the Hubble Space Telescope Imaging Spectrograph (STIS) and the Infrared Telescope Facility SpeX spectrograph. Observations were separated by one week and three months in order to study variability over multiple timesca…
Reapproaching the Spin Estimate of GX 339-4
Miller, J. M.; Cackett, E. M.; Ludlam, R. M.
We systematically reanalyze two previous observations of the black hole (BH) GX 339-4 in the very high and intermediate state taken with XMM-Newton and Suzaku. We utilize up-to-date data reduction procedures and implement the recently developed, self-consistent model for X-ray reflection and relativistic ray tracing, relxill. In the very high and …
The Tip of the Red Giant Branch Distances to Type Ia Supernova Host Galaxies. III. NGC 4038/39 and NGC 5584
Lee, Myung Gyoon; Jang, In Sung
We present the tip of the red giant branch (TRGB) distances to Type Ia supernova (SNe Ia) host galaxies NGC 4038/39 and NGC 5584. Based on the deep images constructed using archival Hubble Space Telescope data, we detect red giant branch stars in each galaxy. VI photometry of the resolved stars and corresponding I-band luminosity functions show th…
Constraining Neutrino Cooling Using the Hot White Dwarf Luminosity Function in the Globular Cluster 47 Tucanae
Hansen, Brad M. S.; Heyl, Jeremy; Richer, Harvey +3 more
We present Hubble Space Telescope observations of the upper part ({T}{eff}\gt {10}4 K) of the white dwarf cooling sequence in the globular cluster 47 Tucanae and measure a luminosity function of hot white dwarfs. Comparison with previous determinations from large-scale field surveys indicates that the previously determined pl…
3C 273 with NuSTAR: Unveiling the Active Galactic Nucleus
Hailey, Charles J.; Fabian, Andrew C.; Brenneman, Laura W. +17 more
We present results from a 244 ks NuSTAR observation of 3C 273 obtained during a cross-calibration campaign with the Chandra, INTEGRAL, Suzaku, Swift, and XMM-Newton observatories. We show that the spectrum, when fit with a power-law model using data from all observatories except INTEGRAL over the 1-78 keV band, leaves significant residuals in the …
Is Flux Rope a Necessary Condition for the Progenitor of Coronal Mass Ejections?
Ouyang, Y.; Yang, K.; Chen, P. F.
A magnetic flux rope structure is believed to exist in most coronal mass ejections (CMEs). However, it has been long debated whether the flux rope exists before eruption or if it is formed during eruption via magnetic reconnection. The controversy has continued because of our lack of routine measurements of the magnetic field in the pre-eruption s…