Chandra X-Ray Observatory

Joint Chandra/HST Accepted Cycle 5 Targets and Abstracts

Proposals from the following HST scientific categories were accepted by the Cycle 12 HST TAC:

Click on the PI Name for the Proposal Abstract

PI NameTitleChandra timeTargets
Eric PerlmanThe Structure and Physics of Extragalactic Jets
3C 264
John BirettaHST / Chandra Monitoring of a Dramatic Flare in the M87 Jet
Jon MillerObservations of Intermediate Mass Black Hole Candidate Ultra-Luminous X-ray Sources
NGC 1313 X-1 and X-2, and M81 X-9 M74 X-1,

Scientific Category: AGN/QUASARS
Title: The Structure and Physics of Extragalactic Jets
PI: Eric Perlman
Approved Chandra Time (Ksecs): 40


As part of an ongoing investigation into the physics of jets, we propose to obtain ACS polarimetry of the jets of 3C 15, 3C 66B, 3C 346, 3C 371 and PKS 0521-36. This builds on our earlier HST work and completes a sample of 9 jets that spans the range of jet luminosities and morphological types. All of these jets have deep, multi-band HST imaging, and radio polarimetry at matching resolution, and all but one has Chandra data. Our goal is to investigate three fundamental issues, brought to light by recent HST and Chandra observations. These are: (1) What is the energetic and magnetic field structure of jets? (2) What is the nature of particle acceleration in jets? (3) What is the nature of the X-ray emission from jets, and what is its relationship to lower energy emissions? Optical polarimetry provides unique information about all of these issues. Because of their vastly different radiative lifetimes (hundreds of years compared to millions), optical and radio polarimetry probe different electron populations and emission regions. Comparison of radio and optical polarimetry can therefore yield direct information about the three-dimensional energetic and magnetic field structure of jets. Optical polarimetry traces the magnetic field configuration in and near electron acceleration regions, and when combined with optical and X-ray spectral index maps, polarimetry can yield key constraints about particle acceleration and the nature of the X-ray emission of jets.

Scientific Category: AGN/QUASARS
Title: HST / Chandra Monitoring of a Dramatic Flare in the M87 Jet
PI: John Biretta
Approved Chandra Time (Ksecs): 35

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 have detected a dramatic flare in knot HST-1 located ~1" from the nucleus. Its brightness has increased ten-fold in the optical band, and continues to increase, and the X-rays show a similarly dramatic outburst. In both bands this HST-1 now rivals 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 four epochs of HST/ACS monitoring during Cycle 12, as well as seven epochs of Chandra/ACIS observation (5ksec each). We also include a brief STIS observation that will be used with prior STIS data to measure proper motions, and ACS polarimetry to map the magnetic field structure. 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.

Scientific Category: GALAXIES
Title: Observations of Intermediate Mass Black Hole Candidate Ultra-Luminous X-ray Sources
PI: Jon Miller
Approved Chandra Time (Ksecs): 40

Ultra-luminous X-ray (ULX) sources are off-nuclear point sources in nearby normal galaxies. Variability observed on the timescale of days, weeks, and years signals that ULXs are accreting sources, likely harboring black holes. However, the observed X-ray luminosity of these systems far exceeds the Eddington limit for a 10 Msun black hole; some ULXs may be intermediate mass black holes. The identification and study of optical counterparts with HST will be central to better understanding these objects. We propose to obtain deep U-B-VI exposures of 4 extremely bright ULXs in nearby spirals: NGC 1313 X-1 and X-2, M81 X-9 (Holmberg II X- 1), and M74 X-1. Each has a 0.5'' Chandra position, and X-ray luminosity and spectral characteristics consistent with expectations for intermediate mass black holes. We will use the colors we obtain, the magnitudes we measure, and any source variability (also, correlated optical-X-ray variability from simultaneous Chandra snapshots) to constrain the nature of the donor stars and the black holes (10 Msun or 100-1000 Msun), and the formation and evolution scenarios for each system.

Last modified: 12/02/10

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