Search Publications
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…
Phase-resolved NuSTAR and Swift-XRT Observations of Magnetar 4U 0142+61
An, Hongjun; Kaspi, Victoria M.; Guillot, Sebastien +12 more
We present temporal and spectral analysis of simultaneous 0.5-79 keV Swift-XRT and Nuclear Spectroscopic Telescope Array observations of the magnetar 4U 0142+61. The pulse profile changes significantly with photon energy between 3 and 35 keV. The pulse fraction increases with energy, reaching a value of ≈20%, similar to that observed in 1E 1841-04…
Measurements of the Mean Diffuse Galactic Light Spectrum in the 0.95-1.65 µm Band from CIBER
Lee, H. M.; Bock, J.; Cooray, A. +14 more
We report measurements of the diffuse galactic light (DGL) spectrum in the near-infrared, spanning the wavelength range 0.95-1.65 µm by the Cosmic Infrared Background ExpeRiment. Using the low-resolution spectrometer calibrated for absolute spectro-photometry, we acquired long-slit spectral images of the total diffuse sky brightness toward s…