文件操作 - 1758611513.M258095P9899.mail.planetcloud-host.com,S=8779,W=8929:2,

文件: /var/vmail/bicar.it/stefano/cur/1758611513.M258095P9899.mail.planetcloud-host.com,S=8779,W=8929:2,

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  17410, 17411
Message-Id: <20250923071149.7D85828802CE@server.astronomerstelegram.org>
Date: Tue, 23 Sep 2025 03:11:49 -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 #17410							     ATEL #17410

Title:	Continued monitoring of PMN J1603-4904: further MeerKAT, NuSTAR,
		and H.E.S.S. epochs
Author:	G. Bruni (INAF-IAPS), M. Brienza (INAF-IRA), J. Rodi (INAF-IAPS),
		G. Migliori, M. Giroletti, E. Liuzzo (INAF-IRA), E. Bronzini (U. Bologna
		&amp; INAF-OAS), M. Kadler (U. Wuerzburg), L. Hernandez-Garcia (U.
		Valparaiso), F. Panessa, E. Torresi, P. Da Vela (INAF-OAS), M. Cerruti
		(U. Paris Cite), , C. Reynolds (CSIRO), P. Goswami (LSW, U. Heidelberg)
		and Stefan J. Wagner, for the H. E.S. S. collaboration
Queries:	gabriele.bruni@inaf.it
Posted:	22 Sep 2025; 10:50 UT
Subjects:Radio, VHE, AGN

We report on further observations of the flaring CSO PMN J1603-4904 performed
with MeerKAT, NuSTAR, and H.E.S.S.. 
MeerKAT carried out a third and a fourth epoch on July 29 and August 29,
2025, respectively. As in the previous epochs, MeerKAT observed the target
for approximately 15 minutes at 3 GHz (S4 band). Phase referencing was
applied, and data were processed using the SARAO Science Data Processor
(SDP) continuum pipeline. The final images have an angular resolution of
4.09" x 3.61", P.A. -62.8 deg, and RMS 36 uJy/beam (Jul 29), while 4.17"
x 3.49", P.A. -57.2 deg, and RMS 43 uJy/beam (Aug 29). The measured flux
density is 1.40+/-0.07 Jy (Jul 29), and 1.39+/-0.07 Jy (Aug 29). These
values are consistent within uncertainties with the previous measurements,
indicating no significant radio variability to date.

The High Energy Stereoscopic System (H.E.S.S.) conducted a second  follow-up
observation of the source at very-high energies (VHE; E>100 GeV) in coordination
with MeerKAT on the night of 29 July 2025, roughly a month after the initial
follow-up (ATel #17307). The offline analysis of about 1.8 h of livetime
revealed no significant excess (detection significance < 1 sigma), indicating
that the source is no longer active in the VHE band. No further coordinated
observations were taken, as the H.E.S.S. visibility is limited after July
due to high zenith constraints.

NuSTAR (Nuclear Spectroscopic Telescope Array) performed DDT observations
from 27 August 6:15:07 to 28 August 1:20:00 2025 UTC, quasi-contemporaneously
with MeerKAT.  Spectral analysis in the 3-20 keV energy range found the
data are well described by an absorbed powerlaw model with an intrinsic
NH = (5.3+/-1.6) x 10^22 /cm^2, Gamma = 3.1+/-0.1 with chi^2/dof = 74.96/73
= 1.03 assuming a galactic absorption of NH = 6.32 x 10^21 /cm^2 and a
redshift of 0.18 (Mueller et al., 2015).  The unabsorbed flux in the 2-10
keV band is about 2.4 x 10^-12 erg/cm^2/s.

<em> 
The MeerKAT telescope is operated by the South African Radio Astronomy
Observatory, which is a facility of the National Research Foundation, an
agency of the Department of Science and Innovation. 
H.E.S.S. is an array of five imaging atmospheric Cherenkov telescopes to
study very-high-energy gamma-ray sources and is located in the Khomas Highlands
in Namibia. It was constructed and is operated by researchers from Armenia,
Australia, Austria, Denmark, France, Germany, Ireland, Japan, the Netherlands,
Poland, South Africa, UK, and the host country, Namibia.  
This research has made use of data from the NuSTAR mission, a project led
by the California Institute of Technology, managed by the Jet Propulsion
Laboratory, and funded by the National Aeronautics and Space Administration.
Data analysis was performed using the NuSTAR Data Analysis Software (NuSTARDAS),
jointly developed by the ASI Science Data Center (SSDC, Italy) and the
California Institute of Technology (USA). 
</em>

------------------------------------------------------------------------------
Password Certification: Gabriele Bruni (gabriele.bruni@inaf.it)
https://www.astronomerstelegram.org/?read=17410
==============================================================================
ATEL #17411							     ATEL #17411

Title:	Swift follow-up of the gamma-ray flaring NLSy1 1H 0323+342
Author:	F. D&#39;Ammando (INAF-IRA Bologna), F. Longo (University
		of Trieste and INFN Trieste), A. Holzmann Airasca (University of Trento
		and INFN Bari) and G. La Mura (INAF - Astronomical Observatory of
		Cagliari)
Queries:	dammando@ira.inaf.it
Posted:	22 Sep 2025; 11:25 UT
Subjects:Optical, Ultra-Violet, X-ray, Gamma Ray, >GeV, Request for
		Observations, AGN, Black Hole, Blazar

Following the gamma-ray flaring activity of the narrow-line Seyfert 1 galaxy
1H 0323+342 (also known as 4FGL J0324.8+3412, Abdollahi et al. 2022, ApJS,
260, 53) detected by Fermi-LAT on 2025 September 20 (ATel #17407), a Swift
target of opportunity observation was performed on September 22.

Swift-XRT data were taken in Photon Counting mode for a total exposure
of about 2.6 ksec. The X-ray spectrum (0.3-10 keV) can be fit by an absorbed
power law model with an HI column density consistent with the Galactic
value in the direction of the source (n_H = 1.27 x 10^21 cm^-2, Kalberla
et al. 2005, A&A, 440, 775) and a photon index of 1.49+/-0.09. The corresponding
intrinsic 0.3-10 keV flux is (7.0+/-0.4) x10^-11 erg cm^-2 s^-1. This flux
is significantly higher than the value observed on 2013 August 30 by Swift-XRT
(ATel #5352) after the previous gamma-ray flaring activity from the source
(ATel #5344). Additionally, the flux observed on 2025 September 22 is higher
than all fluxes observed by Swift-XRT between 2006 and 2018 (D'Ammando
2020, MNRAS, 496, 2213).

Simultaneous Swift-UVOT observations on 2025 September 22 found 1H 0323+342
at an activity level comparable to its brightest states observed by UVOT
between 2006 and 2018 (D'Ammando 2020, MNRAS 498, 859). Specifically, the
observed magnitudes are V = 15.43 +/- 0.05, B = 15.88 +/- 0.05, U = 15.03
+/- 0.05, W1 = 15.21 +/- 0.06, M2 = 15.57 +/- 0.06, W2 = 15.48 +/- 0.06.

New Swift observations are planned. In consideration of the ongoing activity
of this source, confirmed also by the Swift observations, we encourage
further multiwavelength observations. For this source the Fermi-LAT contact
person is Francesco Longo (francesco.longo@ts.infn.it).

We would like to thank the Swift Team for making these observations possible.

------------------------------------------------------------------------------
Password Certification: Filippo D'Ammando (dammando@ira.inaf.it)
https://www.astronomerstelegram.org/?read=17411
==============================================================================

==============================================================================
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 - 1758611513.M258095P9899.mail.planetcloud-host.com,S=8779,W=8929:2,

文件: /var/vmail/bicar.it/stefano/cur/1758611513.M258095P9899.mail.planetcloud-host.com,S=8779,W=8929:2,

编辑文件内容

修改文件时间

删除文件