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RXTE News Archive: 2006 RXTE


New RXTE Software Available (HEAsoft 6.1.2)

December 8, 2006

The latest HEAsoft release (HEAsoft 6.1.2, December 6, 2006) contains a new tool that estimates HEXTE cluster A background, as well as updates to two existing RXTE tools:


    hextebackest - estimates HEXTE Cluster A background (from cluster B)
    fgabor - added WCS keywords to output image.
    hxtrsp - corrected marfrmf call
Clink on the HEAsoft link, above, for instructions on downloading HEAsoft 6.1.2.

Active Galactic Nuclei as scaled-up Galactic Black Holes

December 7, 2006

Using almost 10 years of monitoring observations with RXTE, Ian McHardy and collaborators have found striking new correlations between galactic black holes and active galactic nuclei - evidence that the accretion process is the same in black holes of all sizes. The results, which have implications for the classification of different types of AGN and the understanding of their longterm variability, are published in the December 7 issue of Nature. For further details, see:

RXTE Catches Black Hole Spinning at near Light Speed

November 20, 2006

Researchers Jeff McClintock and Ramesh Narayan have developed a new technique for measuring the spin of a black hole - using RXTE, they've measured the spin of GRS 1915+105 at nearly 0.5c, and report their results in the November 20 issue of The Astrophysical Journal. "The biggest payoff down the road is that we can soon likely get a dozen black hole spin measurements to test all kinds of theories," said McClintock, who is lead author on the report. Implications for Gamma-Ray Burst models and the detection of gravitational waves are also discussed. For further details, see:

RXTE Cycle 12 Announced

October 23, 2006

NASA has announced a new proposal opportunity for RXTE Guest Observer Cycle 12, soliciting proposals for new PCA and/or HEXTE observations to be carried out beginning on or around June 1, 2007. Cycle 12 is expected to last approximately 18 months. Proposals are due January 26, 2007.

Potential proposers should note that this Announcement is solely for the selection of observing time on RXTE and that no funds are available for support of selected proposals. Budgets are not to be submitted in response to this announcement. Observers with proposals accepted through this Announcement may submit funding proposals to the NASA Astrophysics Data Program (ADP).

Further details can be found at http://rxte.gsfc.nasa.gov/docs/cycle12.html. Scientific and technical questions concerning RXTE Cycle 12 should as always be directed to the RXTE Guest Observer Facility via our Feedback form.

HEXTE Cluster "A" Now Fixed-Pointing

October 20, 2006

Earlier this year, HEXTE cluster A experienced more periods where on- and off-source modulation ceased. As this behavior became more frequent, the decision was made to permanently leave HEXTE Cluster A in the on-source position, rather than risk it becoming unrecoverable in an off-source position. The detectors in cluster A are still functioning well and collecting data; HEXTE cluster B also still modulates as normal, and shows no sign of impairment. The HEXTE team has delivered new software that will allow users to generate cluster A background estimates from simultaneous cluster B background files (see Katja Pottschmidt's HEAD poster about hextebackest). The RXTE GOF is now working to make this code available at the next interim HEAsoft (FTOOLS) release, currently scheduled for late November. Before analyzing any HEXTE A data taken in 2006, we recommend users consult the RXTE "Significant Events" page to see whether HEXTE A was fixed or rocking when their data was collected.

When the HEAsoft release containing the new HEXTE tool is available, an announcement will be sent to the XTENEWS mailing list, and will also appear on the RXTE homepage. If you have any questions, please send them to the RXTE GOF using our Feedback form.

RXTE Used to Detect Trans-Neptunian Objects

August 10, 2006

Planetary researchers have devised a novel approach to the search for objects in our solar system beyond Neptune: this week's Nature contains a Letter describing how Hsiang-Kuang Chang et al. used PCA observations of Sco X-1 to search for millisecond occultations that could be caused by small objects beyond Neptune's orbit. Read the fascinating results at:

Nature 442, 660-663(10 August 2006) |doi:10.1038/nature04941 (Hsiang-Kuang Chang, et al.)
Nature "News & Views" article about Chang result

Update: January 2007 Jones, T. A., et al, "Millisecond Dips in Sco X-1 are Likely the Result of High-Energy Particle Events", astro-ph/0612129

New PCA Background Models Released

August 6, 2006

New PCA background models remove long term trends that have become apparent over the years. Only models for "Epoch 5" -- May 2000 to the present -- were changed. The original "Epoch 5" has been divided up into three new intervals, "5A", "5B" and "5C" to account for the trends and improve the background model. New faint and bright source models are available from the links in the table above. The new models have been tested extensively against the background data themselves, as well as by select observers on AGN data. There is marked improvement for faint sources in the energy range 25-30 keV, where a background feature caused artifacts in the previous models.

To learn more, and download the models, visit the PCA Digest Page

Pulsar Quakes Now Predictable!

June 5, 2006

Using RXTE, Dr. John Middleditch (LANL) and collaborators have discovered how to predict earthquake-like events in pulsars. After studying pulsar PSR J0537-6910 over 8 years with RXTE, the team has successfully predicted quakes ("glitches") in time for observation to begin before the event occurs. Their results are being presented at the Calgary AAS this week; for further details, see this press release.

XTE Cycle 11 Budget Deadline Has Passed

March 20, 2006

The deadline for submission of budget proposals for RXTE Cycle 11 stage 2 has passed. We received 59 proposals, which will be reviewed by the budget committee in coming weeks, with results available sometime in June. To see the accepted observing program for Cycle 11, see our Recommended Cycle 11 Program Web page. As always, we thank the community for their continued interest in the RXTE GO program!

RXTE Discovers source of Galactic X-ray Background

February 22, 2006

Mikhail Revnivtsev and collaborators have used RXTE and COBE to show that a large part of the galactic X-ray background may in fact be individual stars - CVs and active stars, to be exact. They estimate that their findings may add more than a billion new objects to the Milky Way's stellar census. The results will be published as two papers in upcoming issues of Astronomy & Astrophysics.

For more information, see:

New Map of Milky Way Reveals Millions of Unseen Objects (NASA Feature Article)

Cycle 11 Budget Information Now Available

February 7, 2006

Successful RXTE Cycle 11 proposers from US institutions are now invited to submit budget requests as part of Cycle 11 Stage 2. PIs working at non-US institutions may have a US co-I submit a budget on their behalf.

You can find information and links to instructions on how to submit through RPS on our Web pages.

Please direct any questions to our helpdesk.

All RXTE Cycle 11 Phase 2 budget requests (hardcopies as well as electronic submissions) must be received by 4:30 PM EST Tuesday, March 14, 2006.

RXTE Researchers receive Rossi Prize!

January 18, 2006

Tod Strohmayer of NASA Goddard Space Flight Center in Greenbelt, Md., Deepto Chakrabarty of the Massachusetts Institute of Technology, and Rudy Wijnands of the University of Amsterdam shared this year's Bruno Rossi Prize for their work on millisecond pulsars, done with RXTE. The Bruno Rossi prize is awarded annually by the High-Energy Astrophyics Division of the American Astronomical Society, in recognition of significant, recent, and original contributions in high-energy astrophysics. Congratulations to the three prize winners! This is the third time that the Rossi prize has been awarded for research done with the Rossi satellite, RXTE!

For further info on this year's prize, read the HEAD Press Release.

For info on the previous Rossi prizes awarded for RXTE research, see:
Kouveliotou Shares Rossi Prize for RXTE Result! (January 15, 2003)
Jean Swank and Hale Bradt share 1999 Rossi Prize (January 11, 1999)

Hot New RXTE Results from the AAS Meeting in Washington, D.C.

January 11, 2006

RXTE scientists have made a splash at AAS Press Conferences with these new results!

  • Scientists Find Black Hole's 'Point of No Return' - Ron Remillard and Dacheng Lin of MIT and Randall Cooper and Ramesh Narayan of the Harvard-Smithsonian Center for Astrophysics in Cambridge used RXTE to "detect" the event horizons around black holes.
  • Spinning Black Hole Leaves Dent in Space-time - Jeroen Homan of MIT, Jon Miller of the University of Michigan, Rudy Wijnands of Amsterdam University and Walter Lewin of MIT report their results from a long, intensive RXTE campaign to observe GRO J1655-40.

December 12, 2005 - January 4, 2006 HEXTE Cluster A Rocking Anomaly

January 8, 2006

Between Dec. 12, 2005 01:26:24 UTC and Jan. 4, 2006 22:40:40 UTC HEXTE cluster A again did not modulate on and off source. As before, the detectors were on, but the cluster position remained fixed for the entire period. Cluster B functioned normally throughout. This time cluster A stopped close to one of the background positions with little exposure to the source. Again a reboot of cluster A and reinitialization of the rocking has restored full function. We believe it is a coincidence that this anomaly occurred very close to one year after the previous anomaly.

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