Possible ALEXIS Transient on Feb. 10

(vsnet-alert 321, Jeff Bloch)

ALEXIS has detected an EUV transient in its 1B telescope (172 Angstroms, 71 eV). There is no detection of the source in the co-aligned 1A telescope (130 Angstroms, 93 eV).

Position: RA,DEC = 13 59 27.6, +53 54 40.3 (J2000 Coordinates) 90% Error Circle Radius = 0.5 degrees

Due to an operational problem, there is no ALEXIS data for 12 hours prior to 23H UT Feb 9. The source was already bright at 0H UT Feb 10, and continued to be active through 06:30H UT Feb 10. The next data dump from ALEXIS will occur around 20UT Feb 10. I will post more information after that time as it becomes available.

Groundbased observations made at this time will aid in the identification of the optical counterpart.

Follow-up information

(vsnet-alert 322)

The analysis of the recently downlinked ALEXIS data is complete.

The transient reported below appears to have peaked in EUV flux at 4:00UT Feb 10, and then began to decline. The source appears to have disappeared by 12UT Feb 10.

Optical properties of such an transient are unknown. For example if it is a previously unknown Cataclysmic Variable, it may still be bright for a few more hours in the optical.

Thanks to all who responded to this alert.


For more information, see the ALEXIS web page


                                                        Jeff Bloch

Jeffrey Bloch                                   Office:    (505) 665-2568
Astrophysics and Radiation Measurements Group   ALEXIS SOC:(505) 665-5975
Los Alamos National Laboratory                  FAX:       (505) 665-4414
Group NIS-2, Mail Stop D436                     e-mail:    jbloch@lanl.gov
Los Alamos, NM 87545                            pager:     104-8074

Optical search by M. Iida

(vsnet-alert 325)

Makoto Iida (Nagano, Japan) checked using a CCD the position around the ALEXIS transient on Feb. 10. The observation was made around Feb. 11.5 UT. He reports there is no new star brighter than 14-th mag. More detailed information might be available from him (QFG00456@niftyserve.or.jp).

Taichi Kato

Information on the field

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