文件操作 - 1752045026.M762956P30515.mail.planetcloud-host.com,S=8362,W=8512:2,

文件: /var/vmail/bicar.it/stefano/cur/1752045026.M762956P30515.mail.planetcloud-host.com,S=8362,W=8512:2,

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  17279, 17280
Message-Id: <20250709071023.2CB06288034B@server.astronomerstelegram.org>
Date: Wed,  9 Jul 2025 03:10:23 -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 #17279							     ATEL #17279

Title:	Einstein Probe detects significant pulsations from AMXP MAXI
		J1957+032 during its 2025 outburst
Author:	Zhaosheng Li (Xiangtan University), L. Kuiper (SRON), Y. Y.
		Pan (Xiangtan University), R. X. Xu (PKU), L. Zhang (IHEP), S. N.
		Zhang (IHEP), S. Zhang (IHEP), J. L. Qu (IHEP), L. M. Song (IHEP),
		Y. P. Chen (IHEP), S. M. Jia (IHEP), M. Y. Ge (IHEP), X. B. Li (IHEP),
		S. J. Zheng (IHEP), Y. Huang (IHEP), Y. Chen (IHEP), L. Tao (IHEP),
		H. Feng (IHEP), W. M. Yuan (NAOC)
Queries:	lizhaosheng@xtu.edu.cn
Posted:	9 Jul 2025; 01:39 UT
Subjects:X-ray, Binary, Neutron Star, Pulsar

Einstein Probe (EP) reported a new outburst from the accreting millisecond
X-ray pulsar (AMXP) MAXI J1957+032 on May 6, 2025 (GCN #40375; see also
ATEL #17170), which lasted for about one week. An EP target of opportunity
(ToO) observation of MAXI J1957+032 was promptly triggered, consisting
of six observations executed between MJD UTC 60801.88 and 60807.26.  We
performed a timing analysis of the EP data taken in timing mode (time resolution
of 23.68 micro s; 13.79 ks total exposure time) during the time window
MJD UTC 60802.73- 60805.47.

We used cleaned timing mode events with energies in the range 0.5-10 keV
extracted from a 35" radius region. These events were barycenter corrected
using the position RA=299.16295 and Dec=+3.44546  (ATEL # 9591) and the
JPL DE421 solar system ephemeris. Starting from the orbital parameters
and constant spin frequency as given in Sanna et al. (2022) (MNRAS 516(1),
L76-L80), we applied a 4d optimization scheme based on a SIMPLEX algorithm
(see e.g. De Falco et al. 2017; Li et al. 2021 for more details) using
the Z22-test statistics.  The  orbital solution assuming a circular orbit
is described by an orbital period of 3652.95(43) s, a projected semi-major
axis ax*sin(i) of 0.013 85(12) lt-s, a time of ascending node Tasc of 60802.746
344(60)  MJD (TDB), while a spin frequency of 313.643 736 8(7) Hz is obtained.
Uncertainties are all given at 1 sigma confidence level.

After correction for the orbital motion we folded the 0.5-10 keV events
upon the optimum spin frequency and obtained an asymmetric double peaked
pulse profile (similar to the NICER profile for the 2022 outburst) at a
significance of 12.9 sigma.

We also searched for the timing signal in NICER data taken between May
11-19, 2025, but we could not detect the pulsed signal in these NICER observations,
very likely, because the source was already in the OFF state (ATEL #17187)
during these observations.

To our knowledge, EP is the only instrument that detects the pulsations
from MAXI J1957+032 during its 2025 outburst, highlighting its potential
timing capabilities during its operation.

------------------------------------------------------------------------------
Password Certification: Zhaosheng Li (lizhaosheng@xtu.edu.cn)
https://www.astronomerstelegram.org/?read=17279
==============================================================================
ATEL #17280							     ATEL #17280

Title:	EP J171159.4-333253/EP250623a: Optical upper limits with Kinder
		and RIFT observations
Author:	A. K. H. Kong (NTHU), A. Aryan (NCU), K.-L. Li (NCKU), T.-W.
		Chen, W.-J. Hou (both NCU), J. H. Gillanders (Oxford), S. J. Smartt
		(Oxford/QUB), Y.-H. Lee, Y. J. Yang, A. Sankar. K, Y.-C. Pan, C.-C.
		Ngeow, M.-H. Lee, H.-C. Lin, C.-H. Lai, H.-Y. Hsiao, C.-S. Lin, J.-K.
		Guo (all NCU), S. Yang, Z. N. Wang, L. L. Fan, G. H. Sun (all HNAS),
		H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford),
		M. Nicholl, M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all
		QUB), A. Schultz and M. Huber (both IfA, Hawaii)
Queries:	akong@phys.nthu.edu.tw
Posted:	9 Jul 2025; 06:28 UT
Subjects:Optical, Binary, Neutron Star, Transient

We observed the eclipsing, bursting neutron star X-ray binary EP J171159.4-333253/EP250623a
(Ni et al. ATel #17247; Wu et al. ATel #17255; Marino et al. ATel #17271)
using the 40 cm SLT at Lulin Observatory in Taiwan as part of the Kinder
collaboration (Chen & Yang et al., 2025, ApJ, 983, 86). The first SLT epoch
of observations started at 14:52 UTC on the 27th of June 2025 (MJD = 60853.619),
3.84d after the EP WXT trigger.

We utilized the astroalign (Beroiz et al. 2020, A&C, 32, 100384) and astropy
(Astropy Collaboration et al. 2022, ApJ, 935, 167) packages to align and
stack the individual frames. We did not find any evidence of a new and
uncataloged source in the stacked images at the position of the proposed
optical (ATel #17272) and radio (ATel #17258) counterparts.

On 3 July 2025, we did another set of follow-up observations with the 0.5-m
RIFT at Lulin from 15:19 to 15:40 UTC. Six 200-s unfiltered images were
taken, and no new source was detected at the reported location.

Moreover, we utilized the Python-based package AutoPhOT (Brennan & Fraser,
2022, A&A, 667, A62) to perform the PSF photometry on our stacked frames.
The details of the observations and measured 3-sigma upper limit  (in the
AB system) are as follows:

SLT | rp | 60853.619 | 300*12 | >18.8 | 2".26 | 1.87

RIFT | white |  60859.638 | 200*6 | >19.0 | 3".81 | 1.90

The presented magnitudes are calibrated using the field stars from the
SkyMapper catalog (r-band) and are not corrected for the expected Galactic
foreground extinction corresponding to a reddening of A_r = 2.5 mag in
the direction of the transient (Schlafly & Finkbeiner 2011).

Based on our observations, the source may brighten on 28 June, 2025 (ATel
#17272) and it has become fainter since 3 July, 2025. We encourage further
monitoring of this source in all wavelengths.

------------------------------------------------------------------------------
Password Certification: Albert Kong (akong@phys.nthu.edu.tw)
https://www.astronomerstelegram.org/?read=17280
==============================================================================

==============================================================================
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 - 1752045026.M762956P30515.mail.planetcloud-host.com,S=8362,W=8512:2,

文件: /var/vmail/bicar.it/stefano/cur/1752045026.M762956P30515.mail.planetcloud-host.com,S=8362,W=8512:2,

编辑文件内容

修改文件时间

删除文件