Affiliation
American Association of Variable Star Observers (AAVSO)
Fri, 08/11/2017 - 19:17
AAVSO Alert Notice 592 announces an observing campaign on V404 Cyg in support of Chandra observations taking place TONIGHT AND TOMORROW. Please see the notice for details and observing instructions, particularly regarding which comparison/callibration stars to use.
Many thanks, and Good observing,
Elizabeth Waagen, AAVSO HQ
Elizabeth
I read the Alert notice and they don't seem to be interested in anything other than R and maybe I filters neither which I have. Are they interested in V,B or CBB (CV) filter observations?
Best!
Pablo
Hi Pablo,
Rc and i' were specified because V404 Cyg is expected to be so faint in V (mag 18) that getting 10 sigma at the needed cadence (faster than 5 minutes) may be really difficult or impossible. B may likely be impossible. That having been said, if you don't have an Rc or i' filter, and you think you can get what they need using V, then I would say to go ahead. Regarding CV, I don't know whether the photometry needed has to be filtered. I mentioned this post to Dr. Sivakoff - he may post with recomendations.
Good observing,
Elizabeth
Elizabeth
Provided I don't have to work tonight and the moon is not too bright I will image V404 Cyg with V and CBB, I agree thet B will be nearly impossible but with the other two and my C14 I may be able to get 10 Sigma at a cadence of 5 minutes each. I will start at 9PM local and continue till about 5AM...
I always keep all the data in external drives anyway and tonight it's not going to be different.
It's a good learning experience for me anyway.
Take care!
Pablo
Well the V and B filters were predictably unusable..but with the Astrodon CBB (Exoplanet) filter I was able to get SNRs as high as 40 with a 300second cadence. I was not able to input the requested comps because I don't know how to do that with vphot yet (Will take the course in October!). However with the standard AAVSO comps I as able to upload photometry through Webobs a few minutes ago . I've attached the AAVSO report here and a screengrab of the comps and check star I used. I can always share the subs on Vphot or the raw data on a dropbox link if needed. I can spend another night observing with CBB if you want to and if you think it's useful but I need to know in less than 2 hrs from now (8PM PDT )otherwise I'll discontinue.
Best!
Pablo
Hi Pablo,
I apologize for not getting back to you yesterday. I was travelling from Friday Night to yesterday and was out of e-mail contact.
The observations with Chandra and VLA were Friday night, so there is no strong need to observe again last night. I'm glad to hear that at least the CBB observations worked. I'll let the collaborators know about the data and I imagine we will be in touch with you. (I'll be posting some more info in a minute).
It looks like we might have caught some flaring behaviour in your data, which is really great!
Hi AAVSO Observers,
First, I apologize for the late notice of this opportunity. Elizabeth and my e-mails to each other had wound up in each other's spam folders. Fortunately Elizabeth checked on Friday and found the couple of weeks old e-mail was able to construct the alert.
I'd like to let you all know what the goals of the observation were. V404 Cyg is a black hole C-ray binary, a black hole that is eating material from a nearby star. While the source underwent a spectacular outburst (feeding frenzy) in 2015, it turns out to be fairly bright between such feeding frenzies.
Our team had approved Chandra X-ray Observatory and Very Large Array simultaneous observations (radio). The goals of these observations were to track how the accretion disk (the source of the black hole's food), and a collimated outflow of material called a jet (aka the black hole's burp) were correlated in quiescence. By measuring the correlation at multiple frequencies, we hope to lean not just how the feeding and burping are related, but also detailed physics about the jet. In particular, we hope to measure the size (and hopefully shape) of the jet. With the VLA we were able to get multiple frequencies of information, but the AAVSO data will be an important middle step between the X-ray and radio information. We'll be looking at the how the shapes of all the data are correlated and the relations across the electromagnetic spectrum at several points in time.
If anyone besides Pablo also has data, please let us know on this forum.
Hi Gregory
Here's the link to my calibrated data (used AstroimageJ), there are 80x300s close to 7 hours worth taken with an Astrodon CBB filter, for some reason Vphot only took 46..I also have the raw subs and calibration files in case you guys want to play with them. I'm tickled pink that I was able to help!
https://www.dropbox.com/sh/erz51qasmqfxyaj/AAAcHYA_zYeTxyIb-_E3PAjZa?dl…
I hope the above link works, otherwise let me know and I will repost.
Take care
Pablo Lewin
Results - not very good. I am re-running my images thru VPHOT after stacking. I'll post them later to WEBOBS if they seem OK. I am having to use a 7 arc sec diaphragm for the star - mostly because of image fuzzyness (seeing, optics, guiding) and VPHOT can't decide which star is V404 CYG. Neither does VSP for that matter.
Lew
Oh, yeah, it was breezy and the big tube was shaken by the wind.