Forum Replies Created
-
Posts
-
At this time of year, a 24h coverage would be possible again just with night observations if there were enough observers around the planet. If I look at the AAVSO database, there are calendar days when we have up to ca 50% coverage: after someone in Europe observes for most of the night, someone in the US takes over … and then we get a gap.
I wonder if there are actually no active T CrB observers in that longitude range? Perhaps there are observers who just don’t bother to submit the data in the absence of an outbreak?
Imagine what it would be like to catch the actual nova outbreak in a high cadence photometry data set! I don’t think this has ever been done for a nova this close.
E.g. there must be tons of Seestar smart telescopes in China that could join the T CrB watch and help close the observation gap. How can we reach out to them?
Cheers
HBEHowever, the 10.17ish from that paper seems to be just the contribution from the Red Giant star in the binary, and what we measure should be the combined flux from the entire binary system including the accretion disk. At the moment, from the AAVSO light curves, I would think a Vmag of 9.8 (fluctuating between 9.75 and 9.85 perhaps) should be about right. If we assume those values and no variability of the donor on short timescales (hours), if my math is right, it would mean that the accretion disk alone, without the red giant donar star, fluctuates between roughly 11.0 mag (V) and 11.3 mag (V) on short timescales, right?
Next meeting: 8th of April:
FWD:========================================================================
This is a REMINDER for our WEBINAR on Tuesday, April 8th at 1700 UTC/1900 FR!
NOTE THE NEW TIMES!!!
Date: Tuesday, April 8th
Time:12:00 PM CDT / 1:00 PM EST / 7:00 PM FR Time / 5:00 PM UTC
1200h CDT/ 1300h EST / 1900h FR / 1700h UTCZoom Link: https://umn.zoom.us/j/8068498577
Guest Speaker:
We’re excited to welcome Dr. Marion Pillas, a postdoctoral fellow at Liege University in Belgium. Dr. Pillas is also the chair for GRANDMA’s GRB Working Group and has written the GRB observing strategy for the collaboration.She will be presenting on her research and on her paper:
“Limits on the Ejecta Mass During the Search for Kilonovae Associated with Neutron Star-Black Hole Mergers: A case study of S230518h, GW230529, S230627c and the Low-Significance Candidate S240422ed”
This paper focuses on how neutron star–black hole (NSBH) mergers are expected to produce kilonovae (KNe), but none have been confirmed despite extensive follow-up of four NSBH candidates detected via gravitational waves during O4 (May 2023 – July 2024). This study evaluates why no KN was detected by analyzing multi-messenger observations and the observational coverage from over 50 instruments. Simulations show that most NSBH KNe peak around one day post-merger in g, r, i bands – often outside follow-up coverage. For some candidates, faint KN luminosity, large distances, or poor sky localization significantly limited detectability, and in one case (S240422ed), the lack of a KN supports a non-astrophysical origin.
This is a GRANDMA/KNC paper led by Dr. Pillas and Dr. Antier. It can be found on the KNC forge, here.
This event is just our webinar, so we hope you’ll take the opportunity to join, ask questions, and learn more about cutting-edge research in fast transients and the science community!
Don’t forget to check out our Youtube for past webinar events and monthly meetings!
See you there!
Cristina Andrade
Research Professional | MN Institute for Astrophysics
The Kilonova Catcher Core Team
http://kilonovacatcher.in2p3.fr/
=============================================================================It’s clear here in Germany 🙂 if you are bored you can watch my live T CrB photometry feed : http://bikeman.selfhost.eu/astro/T_CrB-latest.png
Seriously, I’m not expecting anything to happen this night more than any other night in 2025/2026 wrt T CrB and the measurements tonight might get interrupted from time to time when I try to tweak and test things.
and the next meeting is imminent:
The next telecon (monthly meeting) is tomorrow!
Date: Tuesday, March 25th
Time: 1300h CDT/ 1400h EST / 1900 FR / 1800h UTC
Zoom Link: https://umn.zoom.us/j/8068498577Agenda:
1. Review of activities from the last month. How do you all feel about the alert system?
2. Update on the pre-processing manual.
3. Update on KNC Utilities (FORGE, use of KNC website for images)
4. Update on social media posts.
5. Update on monthly photo challenge: Deep Sky Objects. Currently, no one has submitted any NEW images. If these are not topics you are interested in, please let me know.
6. Update on topic requests. This form has had a few submissions. Thank you!
7. A short presentation by KNC member, Thierry Midavaine, on a topic of interest; a new technology from a company called Prophesee that could be applied to CMOS arrays where you can use machine learning to analyze the rise and fade of each pixel in an image.Regards,
Cristina Andrade
Research Professional | MN Institute for Astrophysics
The Kilonova Catcher Core Team
http://kilonovacatcher.in2p3.fr/I’m not familiar with the S30, but as long as the thing also creates a network share “//Seestar/” in your local network (to pickup frames on the fly), whatever I come up with should be useable for the S30 as well.
I think I’m halfway done now. I’ll be using siril_cli for stacking, astap-cli for plate-solving and first-look photometry and topcat/stilts to generate some checkplots.
While I’m testing this solution (we might have some clear nights over here in the next few days…), the script will upload checkplots generated live to
http://bikeman.selfhost.eu/astro/T_CrB-latest.png
Cloud monitor to go with this: http://bikeman.selfhost.eu/astro/allsky-latest.jpg
but as long as the plots title mentions “TESTING” after the creation-date, you obviously should not trust the results. I think the plots are obvious, they list the measured magnitude for T CrB in the center plus the catalog(blue) and measured(black) magnitudes for up to three comparison stars, for sanity checking. If you see less than 4 red blobs (identified stars for the photometric analysis), the results are inherently wonky.
Actually the hardest part is to come up with good quality checks that should prevent that the script triggers an alarm (which would result in some loud alarm sound and my bedroom lights being switched on) just by some cloud passing the field or some such (like: at leats 2 comp stars have to be matched with “reasonable” magnitude and T CrB is either detected as brightened or not included in the photometry output (which I guess could happen if it saturates).
Of course the idea is that several people all over the planet would do this, so combined we would have a real good chance to catch T CrB very early in the erruption.
Stay tuned
CS
HBEThe next webinar and meeting will be on Tuesday March 18th :
Forwarded from mailing list:
Date: Tuesday, March 18th
Time:1:00 PM CDT / 2:00 PM EST / 7:00 PM FR Time / 6:00 PM UTC
1300h CDT/ 1400h EST / 1900 FR / 1800h UTCZoom Link: https://umn.zoom.us/j/8068498577
Guest Speaker:
We’re excited to welcome Shar Daniels, a 3rd-year Astrophysics PhD student, who will be presenting:“Discovering Fast Optical Transients with Continuous Readout-Mode Imaging”
This talk will explore how continuous readout-mode imaging enables the detection of millisecond-duration optical transients – an emerging frontier in transient astrophysics!
This event is just our webinar, so we hope you’ll take the opportunity to join, ask questions, and learn more about cutting-edge research in fast transients.
See you there!
Cristina Andrade
Research Professional | MN Institute for Astrophysics
The Kilonova Catcher Core Team
http://kilonovacatcher.in2p3.fr/I’ve started work on the “real time photometric alert script”, I hope I can outrun T CrB … My plan is to have this run on a Raspberry Pi, using siril-cli (for stacking (say) 4 x 10 sec exposures (green channel), Source-extractor (for creating a catalog of detected stars and instrumental photometry), scamp for doing the astrometric solution and some custom scripts to check the photometric results for consistency and generate the actual trigger. We will see…
I have started to use my Seestar S50 as a robotic telescope to keep an unattended “eye” on T CrB. It will start observing at 01:00 GMT when the telescope gets a clear LOS on T CrB (from where I can keep it safe) and it will record images for ca 3 hrs atm, and then shut down again, powered by an external powerbank (so I’m not wearing out the internal batteries so much). An errupting T CrB would probably saturate the sensor soonish, but at least I could, when lucky, contribute the initial erruption and some part of the pre-erruption phase.
As the sub-frames are accessible to other computers on my home network (as the Seestar S50 shares it’s storage in the local network as a network drive) it would in theory be possible to script something that would actually monitor T CrB in real-time, unattended, during all of this. Has anyone done this kind of scripting already?
Clear Skies
Heinz-Bernd Eggenstein
