High Energy Network (HEN)

There was just now an alert about a BNS merger

https://gracedb.ligo.org/superevents/S230918aq/view/

but it's not a Gold plated one: There is a significant probability that this was just a false alarm, the sky localization is not great and partly in a part of the sky that is not easy to observe at the moment, and the distance could be rather far away.

Stay tuned!!

HB

This could be interesting: vsnet-alert 27948

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Swift J1727.8-1613: black-hole binary and V404 Cyg-like object ?

 

Swift and MAXI detected an outburst in Swift J1727.8-1613.

This is a candidate for a black-hole binary and possibly similar to

V404 Cyg, a unique object known as a source of rapid variability.

A few seconds variability was already found in X-rays.

The most violent variability would be ~2 mag in several tens of min.

This is very bright. Currently, ~13 mag.

Observing Run O4 for the LIGO/Virgo/Kagra detector network ist set to begin on May 24th 2023. For amateurs of the High Energy Network this aboth could be an interesting time, The hope is that the gravitational wave detectors will detect two neutron stars merging during the next ca 18 months, hopefully in a galxy not too far away. Only one such event has even been observed in gravitational waves and in electromagnetic wavelengths, a second event would be extremely useful for astrophysicists.

Here's a recent success story for amateur GRB observations. A new paper has now been published in the journal "The Astrophysical Journal Letters" with the title

"GRANDMA and HXMT Observations of GRB 221009A: The Standard Luminosity Afterglow of a Hyperluminous Gamma-Ray Burst—In Gedenken an David Alexander Kann" [*]

https://iopscience.iop.org/article/10.3847/2041-8213/acc8d0

There have been numerous GCN Circulars announcing the outburst of GRB 230420A. The posted coordinates are 10:44:09.5, +32:06:38.3. This may be a good target for interested observers.

The GCN Circulars for this event can be found on the new GCN website. Go the the HEN page, click on Miscellaneous Links, GCN Circular Archive, then the "new GCN web site" where you can find the information for GRB 230420A.

Dave

It has come to my attention that in May there will be the 2023 Gravitational Wave Open Data Workshop. This would be an excellent opportunity for those interested in learning about gravitational waves and could possibly produce ideas for new projects or opportunities for AAVSO members. It is a free event that goes from May 15-May 17, 2023. This includes lectures, classes, tutorials, and study groups. The website is https://www.gw-openscience.org/odw/odw2023/. This is sponsored by the LIGO, Virgo and KAGRA (LVK) collaboration.

One of the holy grails of "multimessenger astronomy" is the observation of a merger of two neutron stars resulting in a "kilonova" event. The event is observable in visible light, but to be sure it was really a merger of two neutron stars, you need to detect the gravitational waves generated during the merger. So this is a ideal use case for pro-am collaborations like the KILONOVA-CATCHERS discussed also in this forum: once the professional gravitational wave detectors issue public alarms about an event, amateurs can use their optical telescope to search for the optical counterpart.

 Blazar 4C +31.03 (B2 0110+31) is having an unprecedented outburst.

Sebastian is in the process of putting this blazar into VSX and Elizabeth is developing a general Alert Notice. The J2000 coordinates are RA +01:12:50.34, Dec +32:08:17.4. Any UBVRI observations will be helpful. This object is rapidly brightening and may likewise fade quickly, so observations should be made within the next fer weeks. Thanks.

Dave