- vsnet-alert - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-alert 27490] MAXI J1834-021 (ATel 15932)
by Taichi Kato 06 Mar '23

06 Mar '23

MAXI J1834-021 (ATel 15932) ATEL #15932 ATEL #15932 Title: MAXI J1834-021: Swift/XRT detection and localization Author: J. A. Kennea (PSU), K. L. Page (Leicester) and H. Negoro (Nihon U) Queries: jak51(a)psu.edu Posted: 6 Mar 2023; 21:54 UT Subjects:X-ray, Transient MAXI reported a new X-ray transient, MAXI J1834-021 (ATEL #15929), first seen around February 5th, 2023. On March 6th, 2023 Swift performed a target of opportunity observation, consisting of 7 pointings of 300s each with XRT in Photon Counting mode, in order to cover the MAXI error region. We find a single bright, uncatalogued point source inside the MAXI error region at the following coordinates: RA/Dec(J2000) = 279.0362, -2.2872, which is equivalent to: RA(J2000) =18h 36m 08.70s, Dec(J2000) = -02d 17m 13.9s, with an error radius 3.5 arc-seconds (90% confidence). This position does not much the position of any known X-ray transient, therefore we consider this the likely counterpart of MAXI J1834-021, and confirm that this is a new transient. The position is coincident with two stars in the Gaia EDR3 catalog, Gaia EDR3 4259671048608866560 and Gaia EDR3 4259671052930848384, with magnitudes G=15.84 and G=20.79 respectively. It$B!G(Bs not possible to rule out either counterpart based on the XRT position. The source is bright, with a pile-up corrected count rate of 4.4 +/- 0.6 count/s. The spectrum is well described by an absorbed power-law model, with N_H = 1.46 x 10^22 cm^-2, photon index = 2.2 +/- 1.0 and an observed flux of 2.2 +/- 0.9 x 10^-10 erg/s/cm^2 (0.3-10 keV). We encourage follow-up to identify this new transient.

1 0

[vsnet-alert 27489] Exceptionally high optical state of Blazar PG 1553+113
by Stefan Karge 06 Mar '23

06 Mar '23

Exceptionally high optical state of Blazar PG 1553+113: object date (UTC) mag comment -------------------------------------------------- PG 1553+113 20221225.284 13.88V active, OU, COAST PG 1553+113 20230116.210 13.74V active, OU, COAST PG 1553+113 20230204,147 13.59V active, 20cm-RC, Italy PG 1553+113 20230306,030 13.44V active, 30cm-RC, Italy -------------------------------------------------- PG 1553+113 = 1ES 1553+113 (RA: 15 55 43.0440 Dec: +11 11 24.3656; ICRS J2000). See also ATel #15915. Stefan Karge (SKA) http://quasar.square7.ch/fqm/1553+113.html _______________________________________________

1 0

[vsnet-alert 27488] SSSJ090619.2-275831: superhumps
by Taichi Kato 06 Mar '23

06 Mar '23

SSSJ090619.2-275831: superhumps Josch Hambsch has reported further observations. The data confirm the presence of large-amplitude superhumps. Although the data are still insufficient, a short superhump period (maybe slightly above 0.05 d, many aliases) is suggested. The object may be eclipsing. Further observations are encouraged.

1 0

[vsnet-alert 27487] V589 Her: not an SU UMa star?
by Taichi Kato 06 Mar '23

06 Mar '23

V589 Her: not an SU UMa star? > [vsnet-alert 27477] V589 Her possible superoutburst The object faded rather quickly. ATLAS data since 2016 did not show superoutbursts. The SU UMa-type classification was based on Vanmunter in 2002. I examined the AAVSO data and the profile of the claimed superhumps did not look like very stable, and the object faded too rapidly (0.2 mag/d) for a superoutburst. The classification requires independent observation during a long outburst (but such an one is missing at least recently). YYYYMMDD(UT) mag observer 20230225.7745 <154c (Yutaka Maeda) 20230226.3670 18.409c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230226.3851 18.594c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230226.3900 18.425c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230226.6306 18.390c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230226.6347 18.441c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230226.6496 19.112c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230226.7276 <160c (Yutaka Maeda) 20230227.7272 <156c (Yutaka Maeda) 20230302.3532 15.413c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.3568 15.398c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.3631 15.413c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.7736 148:c (Yutaka Maeda) 20230302.8352 151C (Masayuki Moriyama) 20230304.188 15.89C (Gary Poyner) 20230304.7627 <150c (Yutaka Maeda) 20230305.163 17.07C (Gary Poyner)

1 0

[vsnet-alert 27486] CRTS J161850.8-052509 superoutburst
by Taichi Kato 06 Mar '23

06 Mar '23

CRTS J161850.8-052509 superoutburst ATLAS data apparently show the sign of superhumps. YYYYMMDD(UT) mag observer 20230225.5875 16.339c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230225.5907 16.323c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230225.5968 16.329c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230225.6292 16.349c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230227.3653 16.308c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230227.3657 16.347c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230227.3684 16.328c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230227.3846 16.355c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230227.3940 16.296c (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230301.1066 16.248o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230301.1102 16.124o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230301.1235 16.319o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230301.1343 16.392o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230301.1439 16.298o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.1096 16.265o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.1132 16.321o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.1287 16.446o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.1332 16.494o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230302.1466 16.256o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230303.3380 16.512o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230303.3412 16.604o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230303.3470 16.575o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230303.3525 16.658o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230303.3543 16.592o (ATLAS Forced Photometry (Tonry+2018, PASP 130, 064505)) 20230304.8408 166C (Masayuki Moriyama)

1 0

[vsnet-alert 27485] MASTER OT J193922.39+665346.0 likely superoutburst
by Taichi Kato 06 Mar '23

06 Mar '23

MASTER OT J193922.39+665346.0 likely superoutburst (Known SU UMa star. Short supercycle) YYYYMMDD(UT) mag observer 20230225.8624 <162c (Yutaka Maeda) 20230227.8140 <142c (Yutaka Maeda) 20230302.8611 <157c (Yutaka Maeda) 20230304.8500 151:c (Yutaka Maeda)

1 0

[vsnet-alert 27484] SSSJ090619.2-275831: large-amplitude variation
by Taichi Kato 05 Mar '23

05 Mar '23

SSSJ090619.2-275831: large-amplitude variation Josch Hambsch has reported observations. Large-amplitude (0.2-0.3 mag) variations were recorded, but are not yet securely identified as superhumps. More observations will clarify the nature.

1 0

[vsnet-alert 27483] MASTER OT J055845.55+391533.4: dip and rebrightening
by Taichi Kato 05 Mar '23

05 Mar '23

MASTER OT J055845.55+391533.4: dip and rebrightening According to observations by Itoh-san, this object faded to 16.8 (dip) on Mar. 2 and brightened again to 15.4 on Mar. 3. Superhumps are not currently apparent.

1 0

[vsnet-alert 27482] ASASSN-20av superoutburst
by Taichi Kato 05 Mar '23

05 Mar '23

ASASSN-20av superoutburst Known SU UMa star. YYYYMMDD(UT) mag observer 20230224.508 <180C (Mitsutaka Hiraga) 20230302.528 160C (Mitsutaka Hiraga) 20230303.462 163C (Mitsutaka Hiraga)

1 0

[vsnet-alert 27481] Gaia23ays
by Taichi Kato 04 Mar '23

04 Mar '23

Gaia23ays http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia23ays/ Gaia23ays AT2023cta 2023-03-03 07:01:55 184.30874 -38.00620 16.25 unknown 2023-03-04 09:09:22 apparently hostless blue transient 121714.051 -380019.24 (2000.0) GALEX_DR5_6386115440733588477 NUV=21.304(0.368) FUV=-(-)

1 0

2025

2024

2023

2022

2021

vsnet-alert