文件操作 - 1757747184.M625730P21584.mail.planetcloud-host.com,S=5906,W=6003:2,

文件: /var/vmail/bicar.it/stefano/cur/1757747184.M625730P21584.mail.planetcloud-host.com,S=5906,W=6003:2,

编辑文件内容

Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=174.142.199.243; helo=server.astronomerstelegram.org; envelope-from=atel@astronomerstelegram.org; receiver=stefano@bicar.it 
To: stefano@bicar.it
From: atel@astronomerstelegram.org
Subject: ATel  17388
Message-Id: <20250913070621.258DB2880833@server.astronomerstelegram.org>
Date: Sat, 13 Sep 2025 03:06:21 -0400 (EDT)

------------------------------------------------------------------------------ 
The Astronomer's Telegram is free to read, free to publish, free to
use.  Thanks to the support of our patrons, we can continue to
keep it free. https://www.patreon.com/astronomerstel
------------------------------------------------------------------------------ 
The Astronomer's Telegram                   http://www.astronomerstelegram.org 
------------------------------------------------------------------------------
Posted: Within the last 24 hours
==============================================================================
ATEL #17388							     ATEL #17388

Title:	Detection of Type-II bursts from the Rapid Burster by XSPECT
		on-board XPoSat
Author:	Rwitika Chatterjee, Koushal Vadodariya, Vivek K. Agrawal,
		Radhakrishna V., Piyush Kumar Gaurav, Sachin Narang, Madhu K V, Shyam
		Prakash V P, Vaishali Sharan, Valluru Uma Maheshwara Rao, Jayashree
		Jana Bhattacharya, Thameemunnisha M, Anandraj R, Shivam Asati (U.
		R. Rao Satelllite Centre; ISRO Telemetry, Tracking and Command Network)
Queries:	rwitika@ursc.gov.in
Posted:	12 Sep 2025; 12:32 UT
Subjects:X-ray, Binary, Neutron Star, Transient, Variables

MXB 1730-335, more popularly known as the Rapid Burster, is a transient
neutron star low mass X-ray binary (NS-LMXB), located in the globular cluster
Liller 1 at a distance of ~7.9 kpc. It is one of only two known neutron
star sources, which shows type-II bursts, and the only source which shows
both type-I and type-II bursts. The source goes into an active phase with
a typical recurrence time of ~100 days (Masetti 2002). Anticipating such
a phase, as well as monitoring MAXI fluxes, XSPECT (X-ray SPECtroscopy
and Timing) instrument (Vatedka et al. 2025, Chatterjee et al. 2025) on-board
XPoSat triggered a ToO observation to observe this source.

XPoSat observed the Rapid Burster on 2025 September 5-6, and between 05:30
UT to 14:15 UT of September 5, XSPECT detected four type-II bursts. For
two of these, the complete burst profile was traced (see Figure at <a href="https://github.com/rwitika/xspect_figures/blob/a5c68366a83cc32189cfbcedff02c98070bc6f9c/xspect_rapidburster_figure.pdf"
target="_blank">this link</a>), while for the other two, only partial burst
profiles could be captured due to gaps in observing window owing to mission
constraints. The bursts show the typical profile of type-II bursts, with
a somewhat raised &apos;hump&apos; before the burst, and a slight dip just
preceding a rapid increase. This is followed by an almost flat top, a decline
to an intermediate level and finally reaching the pre-burst level.

XSPECT consists of co-aligned square collimators of 2&deg; &times; 2&deg;
and 3&deg; &times; 3&deg; FOVs. Due to the proximity of this source with
another source (4U 1728-34, ~0.5&deg; away), this observation was carried
out in offset pointing mode, ensuring that only the rapid burster is present
in the 2&deg; &times; 2&deg; FOV. Hence, we used the data from eight of
the sixteen detectors having 2&deg; &times; 2&deg; collimators. After accounting
for the collimator response, the background-subtracted pre-burst count
rate is 2.1 &plusmn; 0.4 cps, and it rises to 10.7 &plusmn; 1.0 cps and
12.1 &plusmn; 1.1 cps (for the two fully traced profiles) during the flat
top of the burst. These two bursts lasts for about 650 s and 250 s respectively,
and are possibly mode-0 bursts, according to the classification scheme
of Bagnoli et al. (2015).

We fitted the pre-burst spectrum with an absorbed powerlaw, which gave
an unabsorbed 0.8 - 15 keV flux of 36 &plusmn; 3 mCrab. The burst spectrum
is well-fitted by an absorbed blackbody model, yielding a best-fit blackbody
temperature of ~ 1.4 keV, and a flux of 205 &plusmn; 5 mCrab. Follow-up
observations of this source are ongoing.

The XPoSat project is managed and facilitated by the Indian Space Research
Organisation.

------------------------------------------------------------------------------
Password Certification: Rwitika Chatterjee (rwitika@ursc.gov.in)
https://www.astronomerstelegram.org/?read=17388
==============================================================================

==============================================================================
This is an automatically-generated notice.  You can remove yourself permanently
from receiving both the Daily Email Digest and Instant Email Notices from
The Astronomer's Telegram by following this link:
https://www.astronomerstelegram.org?unsubscribe&confirmation=a803d34e7ea924f9a4142bac00763549&address=stefano@bicar.it

文件操作 - 1757747184.M625730P21584.mail.planetcloud-host.com,S=5906,W=6003:2,

文件: /var/vmail/bicar.it/stefano/cur/1757747184.M625730P21584.mail.planetcloud-host.com,S=5906,W=6003:2,

编辑文件内容

修改文件时间

删除文件