Search Publications
Direct Detection of Seasonal Changes on Triton with Hubble Space Telescope
Buratti, Bonnie J.; Bauer, James M.; Li, Jian-Yang +4 more
Triton is one of the few bodies in the solar system with observed cryo-volcanic activity, in the form of plumes at its south pole, which suggests large-scale surface volatile transport over time. Triton's large variations in obliquity have motivated prior predictions of changing atmospheric column densities of several orders of magnitude, driven b…
A Detailed Study of the Rise Phase of a Long Duration X-Ray Flare in the Young Star TWA 11B
Micela, G.; Reale, F.; López-Santiago, J. +1 more
We analyzed a long duration flare observed in a serendipitous XMM-Newton detection of the M star CD-39 7717B (TWA 11B), member of the young stellar association TW Hya (~8 Myr). Only the rise phase (with a duration of ~35 ks) and possibly the flare peak were observed. We took advantage of the high count rate of the X-ray source to carry out a detai…
Gas Accretion in the M32 Nucleus: Past and Present
Seth, Anil C.
Using adaptive optics assisted Gemini/NIFS data, I study the present and past gas accretion in the central 3'' of the M32 nucleus. From changes in the spectral slope and CO line depths near the center, I find evidence for unresolved dust emission resulting from black hole (BH) accretion. With a luminosity of ~2 × 1038 erg s-1…
D/H ratio of Titan from Observations of the Cassini/Composite Infrared Spectrometer
Flasar, F. M.; Achterberg, R. K.; Jennings, D. E. +9 more
The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft, launched in 1997 October and inserted into Saturn's orbit in 2004 July for exploration of the Saturnian system, has been making observations of Titan during its close flybys. The infrared spectra of Titan observed over a wide range of latitudes cover the 10-1400 cm-1
On the Radial Extent of the Dwarf Irregular Galaxy IC10
Walker, A. R.; Prada Moroni, P. G.; Degl'Innocenti, S. +15 more
We present new deep and accurate space (Advanced Camera for Surveys-Wide Field Planetary Camera 2 on board the Hubble Space Telescope) and ground-based (Suprime-Cam at Subaru Telescope, Mega-Cam at Canada-France-Hawaii Telescope) photometric and astrometric data for the Local Group dwarf irregular IC10. We confirm the significant decrease of the y…
Swift Observations of the Ultraluminous X-ray Source Holmberg IX X-1
Kaaret, P.; Kong, A. K. H.; Feng, H. +2 more
Holmberg IX X-1 is a well-known ultraluminous X-ray source with an X-ray luminosity of ~1040 erg s-1. The source has been monitored by the X-ray telescope of Swift regularly. Since 2009 April, the source has been in an extended low luminosity state. We utilize the co-added spectra taken at different luminosity states to study…
Vestige of the Star Cluster Burst in M51
Hwang, Narae; Lee, Myung Gyoon
We present a study of the star cluster formation in M51 based on the image data taken with Advanced Camera for Surveys (ACS) and Wide Field Planetary Camera 2 (WFPC2) of Hubble Space Telescope (HST). We have derived the star cluster formation rate using the ages and masses of about 2000 star clusters estimated by comparing photometric data (F336W,…
Search for High-energy Gamma-ray Emission from an Anomalous X-ray Pulsar, 4U 0142+61
Göǧüş, Ersin; Şaşmaz Muş, Sinem
Until 2004, anomalous X-ray pulsars (AXPs) were known as strong emitters of soft X-rays only (<10 keV). The discovery of hard X-ray component from AXPs provided important insight about their emission properties while it posed a serious challenge to explain its origin. The physical mechanism of the hard emission component has still not been full…
Thickness of the Heliosheath, Return of the Pick-up Ions, and Voyager 1's Crossing the Heliopause
Hsieh, K. C.; Giacalone, J.; Hilchenbach, M. +3 more
Using results of remote sensing by energetic neutral atoms from IBEX, SOHO/HSTOF, and Cassini/INCA, in situ measurements of ~40-4000 keV protons in the heliosheath (HS) from Low Energy Charged Particle on Voyager 1 and Voyager 2, and outputs from numerical modeling of the termination shock, we estimate L, the characteristic thickness of the HS in …
Discovery of a Multipolar Structure with an Equatorial disk in NGC 6072
Zhang, Yong; Kwok, Sun; Hsia, Chih-Hao +2 more
From near-infrared and molecular hydrogen imaging observations, we have discovered that the planetary nebula NGC 6072 has a multipolar structure with a prominent equatorial ring. We have modeled the object by a double bipolar system, each with an equatorial ring and a pair of bipolar lobes. The bipolar axes of the two systems are estimated to be s…