[vsnet-alert 8615] Re: ATel 579. ***Instant Email Notice***: Transients

[Daisaku NOGAMI]

Dear colleagues,

RXTE All-Sky Monitor discovered a new transient X-ray object which
is likely a black hole transient (Levine et al., ATEL #578).  The
position was measured to be 18h18m25s, -24o31'12" (J2000) with an
uncertainty of about 1 arcmin, as below (Markwardt et al., ATEL
#579).  Follow-up observations in all the wavelengths are recommended!

Best regards,
Daisaku Nogami
VSNET Collaboation Team 

On 16 Aug 2005 17:28:47 -0000 in ATel  579. ***Instant Email Notice***: Transients ,
atel at astronomerstelegram.org wrote:

> ***Instant Email Notice***: Transients
> 
> ------------------------------------------------------------------------------ 
> ------------------------------------------------------------------------------ 
> The Astronomer's Telegram                   http://www.astronomerstelegram.org 
> ==============================================================================
> ATEL #579							     ATEL #579
> 
> Title:		RXTE PCA Position for XTE J1818-245
> Author:		C. B. Markwardt (GSFC/UMD), T. E. Strohmayer (GSFC), J. H.
> 		Swank (GSFC), A. M. Levine (MIT)
> Queries:	craigm at milkyway.gsfc.nasa.gov
> Posted:		16 Aug 2005;  17:28  UT
> Subjects:	X-ray, Binaries, Black Holes, Transients
> 
> 
> 
> RXTE observed the position of XTE J1818-245 (ATEL #578) on Aug 16, 
> 04:19 to 05:15 UT.  The observation included both pointed data and a 
> cross scan for position.  We note the corrected source name.      
> 
> The best fit position is R.A., Dec.   = 274.605, -24.542 deg (J2000),
> with an estimated systematic position   uncertainty of ~1 arcmin.  This
> position is approximately 50 arcsec   from the ASM position reported in
> ATEL #578 by Levine et al.      
> 
> The spectrum is reasonably well fit by a strong soft thermal component
> (kT ~ 0.5 keV) plus a steep power law (gamma ~2.6), and a feature near
> 6.4 keV.  The X-ray fluxes in the 2-10, 10-20 and 20-40 keV bands are
> 77, 1.7 and 1.4 times 1E-10 erg cmE-2 sE-1.      
> 
> No pulsations are detected.  As noted by Levine et al (ATEL #578),
> these behaviors are suggestive of a black hole transient.  
> 
> ------------------------------------------------------------------------------
> Password Certification:  Craig B. Markwardt (craigm at lheamail.gsfc.nasa.gov)
> http://www.astronomerstelegram.org/?read=579
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> 
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