[vsnet-alert 23968] Re: AT 2019zhd = ZTF19adakuot outburst

[FIDRICH Róbert fidusz@gmail.com via vsnet-alert]

This is AT 2019zhd

https://wis-tns.weizmann.ac.il/object/2019zhd

Classification by Miho Kawabata:

"2020-02-14 13:13:47

The spectrum shows the strong emission lines of H-alpha and H-beta with 
the blue continuum. The FWHM of the H-alpha is measured to be around 
1000km/s. The emission line peaks of H-alpha and H-beta are blueshifted 
to 400-500km/s, which is consistent with the helioncetric velocity of 
M31 within error. These features are possibly similar to that of the 
luminous blue variable, while the spectrum cannot be distinguished from 
the luminous red nova."

Clear skies,

Best,

Robert Fidrich
HAA/VSS


2020. 02. 14. 12:35 keltezéssel, Denis Denisenko d.v.denisenko at gmail.com 
via vsnet-alert írta:
> Something unusual has exploded in Andromeda galaxy M31 (or in our own Milky
> Way in front of M31). The object was originally discovered by ZTF on 2019
> Dec. 14 at 20.35r magnitude. After two months of "pumping-up" it has
> suddenly brightened by 4m in less than 4 days:
> https://lasair.roe.ac.uk/object/ZTF19adakuot/
> 
> ZTF19adakuot
>    20200208.112   18.72r  ZTF Lasair
>    20200208.178   19.18g  ZTF Lasair
>    20200212.113   15.44r  ZTF Lasair
>    20200212.159   15.39g  ZTF Lasair
> 
> Object has been also reported to CBAT TOCP by somebody from Japan, judging
> from the observing time:
> http://www.cbat.eps.harvard.edu/unconf/followups/J00403785+4034529.html
> 
> PNV J00403785+4034529
>    20200213.4600  14.9U   CBAT TOCP
> Offset from M31 nucleus: 1441" West, 2476" South
> 
> For M31 distance modulus of m-M=24.4, ZTF magnitude corresponds to M=-9 and
> TOCP magnitude to M=-9.5. The brightest "nova" in M31 (2008-11b at 14.7)
> was not a classical Nova, but a foreground dwarf nova.
> 
> By the coincidence, there was a gravitational wave signal S200213t at
> 04:12:39 UTC with the 90% confidence level localization area including M31:
> https://gracedb.ligo.org/superevents/S200213t/
> 
> M110 was mentioned by P. Evans among 20 most possible host galaxies of
> S200213t in GCN 27045: https://gcn.gsfc.nasa.gov/gcn3/27045.gcn3
> 
> Spectroscopy and follow-up multi-color photometry are urgently needed.
> 
> Denis Denisenko
>