Chandra X-Ray Observatory

Joint Chandra/HST Accepted Cycle 6 Targets and Abstracts

Proposals from the following HST scientific categories were accepted by the Cycle 13 HST TAC:

Click on the PI Name for the Proposal Abstract

PI NameTitleChandra timeTargets
Aaron BarthA Multiwavelength Study of POX 52, A dwarf Seyfert Galaxy with an Intermediate-Mass Black Hole
POX 52
John BirettaHST/Chandra Monitoring of a Dramatic Flare in the M87 Jet
NGC 4486

Scientific Category: AGN/Quasars
Title: A Multiwavelength Study of POX 52, A dwarf Seyfert Galaxy with an Intermediate-Mass Black Hole
PI: Aaron Barth
Approved Chandra Time (Ksecs): 25


We propose a comprehensive optical, UV, and X-ray investigation of the unique galaxy POX 52. POX 52 is a Seyfert 1 galaxy with unprecedented properties: its host galaxy appears to be a dwarf elliptical, and its stellar velocity dispersion is only 36 km/s. The stellar velocity dispersion and the broad emission-line widths both suggest a black hole mass of order 10^5 solar masses, placing POX 52 in a region of AGN parameter space that is almost completely unexplored at present. We request ACS/HRC imaging to perform a definitive measurement of the host galaxy structure; STIS UV and optical spectroscopy to study the nonstellar continuum and the structure of the broad-line region; and Chandra ACS imagin to detect the X-ray emission from the nucleus and investigate its spectral and variability properties. The results of this program will give a detailed understanding of the host galaxy and accretion properties of one of the very few known black holes in the mass range around 10^5 solar masses.

Scientific Category: Jets, AGN Physics, BL LAC Objects and Blazars
Title: HST/Chandra Monitoring of a Dramatic Flare in the M87 Jet
PI: John Biretta
Approved Chandra Time (Ksecs): 60


As the nearest galaxy with an optical jet, M87 affords an unparalleled opportunity to study extragalactic jet phenomena at the highest resolution. During 2002, HST and Chandra monitoring of the M87 jet detected a dramatic flare in knot HST-1 located ~1" from the nucleus. As of late 2003 its brightness has increased twenty-fold in the optical band, and continues to increase sharply; the X-rays show a similarly dramatic outburst. In both bands HST-1 now greatly exceeds the nucleus in brightness. To our knowledge this is the first incidence of an optical or X-ray outburst from a jet region which is spatially distinct from the core source; this presents an unprecedented opportunity to study the processes responsible for non-thermal variability and the X-ray emission.

We propose seven epochs of HST/STIS monitoring during Cycle 13, as well as seven epochs of Chandra/ACIS observation (5ksec each). We also include a brief HRC/ACS observations that will be used to gather spectral information and map the magnetic field structure. This monitoring is continued into Cycles 14 and 15.

The results of this investigation are of key importance not only for understanding the nature of the X-ray emission of the M87 jet, but also for understanding flares in blazar jets, which are highly variable, but where we have never before been able to resolve the flaring region in the optical or X-rays. These observations will allow us to test synchrotron emission models for the X-ray outburst, constrain particle acceleration and loss timescales, and study the jet dynamics associated with this flaring component.

Last modified: 12/02/10

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