文件操作 - 1743923479.M522154P30066.mail.planetcloud-host.com,S=7521,W=7669:2,

文件: /var/vmail/bicar.it/stefano/cur/1743923479.M522154P30066.mail.planetcloud-host.com,S=7521,W=7669:2,

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  17132, 17133
Message-Id: <20250406071115.CBAE528808DB@server.astronomerstelegram.org>
Date: Sun,  6 Apr 2025 03:11:15 -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 #17132							     ATEL #17132

Title:	NuSTAR detects a source consistent with the location of the
		transient Swift J174610-290018
Author:	B. Grefenstette (Caltech), K. Forster (Caltech), S. Zhang
		(MSU), K. Mori (Columbia)
Queries:	bwgref@srl.caltech.edu
Posted:	5 Apr 2025; 20:57 UT
Subjects:X-ray, Black Hole, Neutron Star, Transient

During an observation of the Galactic Center on 2025-04-04 (NuSTAR Program
10022, PI S Zhang), in the first 18-ks of exposure NuSTAR clearly detected
a point source at a location that is consistent with that of Swift J174610-290018
(ATEL #16481). The NuSTAR SOC routinely checks for the presence of new
transients when this does not conflict with the science of the program
of the PI.

The NuSTAR 3-10 keV positions from the two telescopes are:

FPMA:

R.A.: 17:46:10

Dec.: -29:00:08.780

and

FPMB:

R.A.: 17:46:10.8549

Dec.: -29:00:14.5

...with systematic uncertainty in the astrometry of a roughly 5-arcsec.
These are offset from the positions reported by Neil-Gehrels Swift/XRT
in Feb 2024 (ATEL #16481) by 9 and 6-arcsec, respectively. We therefore
propose that this is a re-brightening of this transient source.

We also checked recent NuSTAR observations of the Galactic Center on 2025-03-09
(NuSTAR Program 10090, PI K. Mori) and do not see the source in the quicklook
images, implying that this source brightened between the two NuSTAR observations.

Using counts extracted from a source region 30-arcsec from the centroids,
we find that the source is clearly detected in the 3-10 keV band and is
well fit by an absorbed, soft spectrum that is alternatively well-fit by
a soft power-law (Gamma>2) or a hot diskbb (Tin > 2 keV), though these
parameters are poorly constrained and degenerate with the amount of absorption.
With Nh == 20e22 cm^-2 for comparison with the Swift analysis and using
a tbabs(po) model we find (fitting over the 3-10 keV) range:

Gamma: 2.6 ± 0.2

...and a 3-10 keV flux of 4.7 - 5.2e-12 ergs / sec / cm^2. This is comparable
to the flux found in 2024 by Swift.

Further observations are planned for ongoing programs that will be able
to monitor the flux at this location over the coming weeks but we encourage
follow-up with other observatories.

------------------------------------------------------------------------------
Password Certification: Brian Grefenstette (Bwgref@srl.caltech.edu)
https://www.astronomerstelegram.org/?read=17132
==============================================================================
ATEL #17133							     ATEL #17133

Title:	Fermi-LAT detection of enhanced gamma-ray activity from the
		FSRQ PKS 0907-023
Author:	Adithiya Dinesh (Universidad Complutense de Madrid), Janeth
		Valverde (Marquette University) , on behalf of the Fermi Large Area
		Telescope Collaboration
Queries:	adinesh@ucm.es
Posted:	5 Apr 2025; 23:54 UT
Subjects:Gamma Ray, >GeV, VHE, AGN, Blazar, Quasar

The Large Area Telescope (LAT), one of the two instruments on the Fermi
Gamma-ray Space Telescope, has observed enhanced gamma-ray activity from
a source positionally consistent with the flat-spectrum radio quasar PKS
0907-023, also known as 4FGL J0909.7-0230 (4FGL; The Fermi-LAT collaboration
2020, ApJS, 247, 33), with coordinates R.A. = 137.43718 deg, Dec. =  -2.52510
deg (J2000; Hunt et al. 2021, AJ, 162, 121), and redshift z=0.957 (Xiao
et al. 2022, ApJ, 936, 146).

Preliminary analysis indicates that this source was in an elevated gamma-ray
emission state on April 4, 2025, with a daily averaged gamma-ray flux (E>100MeV)
of (0.5+/-0.2) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only).
This corresponds to a flux increase of a factor of 16 relative to the average
flux reported in the fourth Fermi-LAT catalog (4FGL). This is the highest
LAT daily flux ever observed for this source. The corresponding photon
index is 1.9+/-0.2, indicating a significantly harder state than the 4FGL
value of 2.29+/-0.02. The hard spectral state led to the observation of
a high-energy photon of E = 15 GeV, associated with the source with a probability
p > 0.999.

Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray
monitoring of this source will continue.  A preliminary light curve for
PKS 0907-023 can be accessed via the Fermi-LAT Light-Curve Repository at
<a href="https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source.html?source_name=4FGL_J0909.7-0230">4FGL
J0909.7-0230</a>. We encourage multifrequency observations of this source.
For this source, the Fermi-LAT contact persons are Adithiya Dinesh (adinesh@ucm.es)
and Janeth Valverde (janeth@umbc.edu).

The Fermi-LAT is a pair conversion telescope designed to cover the energy
band from 20 MeV to greater than 300 GeV. It is the product of an international
collaboration between NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden.

------------------------------------------------------------------------------
Password Certification: Janeth Valverde (valverde@llr.in2p3.fr)
https://www.astronomerstelegram.org/?read=17133
==============================================================================

==============================================================================
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 - 1743923479.M522154P30066.mail.planetcloud-host.com,S=7521,W=7669:2,

文件: /var/vmail/bicar.it/stefano/cur/1743923479.M522154P30066.mail.planetcloud-host.com,S=7521,W=7669:2,

编辑文件内容

修改文件时间

删除文件