Affiliation
American Association of Variable Star Observers (AAVSO)
Thu, 02/04/2016 - 20:09
AAVSO Special Notice #412 announces a radio observing campaign on SS Cyg. An Alert Notice will be issued February 5 with full information. Beginning at once, close monitoring of SS Cyg and immediate submission of observations to the AAVSO is essential in order to catch the beginning of the next outburst, which is imminent.
Thank you, and good observing,
Elizabeth Waagen, AAVSO HQ
Further to the radio observing campaign on SS Cyg announced in Special Notice #412, AAVSO Alert Notice 536 has been published.
Many thanks for your crucial observations to date; please keep up the excellent work!
Good observing,
Elizabeth Waagen, AAVSO HQ
After checking the light curve, it looks to me like SS Cyg has started up. What are others thinking?
Whit Ludington
Except for limited northerly sites, monitoring SS Cyg is difficult or impossible this time of the year! I have noticed on many prior occasions too, the professionals who schedule the campaigns seem to be oblivious to "observing seasons", and when objects of interest are convenient and/or accessible to ground-based amateur observers.
Maybe AAVSO should create a custom online "planning tool" which would allow professionals to select object and/or seasons when their targets could be easily observed for the collaborations.
Thanks,
Mike (where SS Cyg is unobservable from Hawaii :(
I have to admit, I was thinking just what Mike posted. While these stars will do what they do, and whenever they do it, it seems we have had a number of requests for close observation of targets that are way off to the West, and difficult to observe. Do professional astronomers actually understand opposition, or do they just have no control over the timing of their observational time on the premeire instruments?
I can see that SS Cyg is up again before sunrise from my location (+44 also), but I don't get many chances to make observations at that time, and given the cold winter weather (expected to be around -25F here by morning) the dome shutters at my local observatory get a little cranky and cantankerous (as I do, I suppose), so I may not be able to rely on our automated systems to work 100%. I hope a good number of people can get good data on it, but I fear I probably can't.
Clear skies,
Brad Vietje
Newbury, VT
HI All,
First off, thanks for the feedback about the negative timing of the campaign on the current SS Cyg outburst. While I can't speak for others, as one of the professional astronomers involved in this campaign, I wanted to briefly discuss some of the considerations that we made when requesting this particular campaign. I also want to indicate how we might do better in the future.
For this multiwavelength campaign, our plan was to combine AAVSO data with data from two radio telescopes, eMERLIN and AMI, and one X-ray telescope, Swift. Optical data from AAVSO is affected strongly by the Sun's position in the celestial sky. Swift's capacity is also limited by solar and lunar constraints. The radio facilities have much more flexibility for solar and lunar constraints.
However, in the case of the professional facilities, we are limited by at what times our proposed observations are accepted. In this case, the primary driver for this was eMERLIN; we only had time approved that would correspond to a few outbursts of SS Cyg. But, AMI was undergoing upgrades during the first few outbursts. The first opportunity when both were working occurred over Christmas. Besides being a difficult time to coordinate observations across multiple observatories, there were some transient events occurring then that we knew would have high priority on these instruments. This left the current outburst and (perhaps) the next one.
While we would have preferred to wait for a better observing season, we did not want to rely on waiting for the next outburst and hoping it occurred while the eMERLIN proposal was still valid. Thus, we made the choice to start the campaign on this outburst, knowing that, unfortunately, coverage would be limited to those observers at Northern latitudes. We fully appreciate not just those observers that got data, but those that wish they could have taken data if conditions were better.
The good news about this choice is that with AAVSO, we will have the first data from an anomalous outburst with SS Cyg with both radio and optical coverage. But because this outburst was anomalous and there had never been radio coverage of such an outburst before, we had to hold off on our eMERLIN observations.
Given this, we are hopeful that we will be able to extend the period over which the eMERLIN observations can be done. We will likely try to arrange a second campaign (probably on the next outburst). Given the position of SS Cyg, more observers should be able to participate. But we recognize that for some observers, this will still either be tough or impossible.
While in this case, we had less control over when we could observe than we would have liked. Mike and Brad rightfully ask whether the professional astronomers could make better choices when working closely with the AAVSO observers.
I will admit that sometimes, my access to radio ground-based / space-based observatories has led me to forget when a source will be up for ground-based observers, especially for rare transient events. While I personally tend to check tools for when they can be observed, I don't always check it for a wide range of latitudes. This is one area I can improve on personally. I am also involved with a group of astronomers who are developing material to aid astronomers in planning simultaneous multi-wavelength observations. I will be sure to include advice on matching ground-based optical capacity to radio or space-based capacities.
As for tools, I am unfortunately too swamped to develop a tool for the AAVSO, but I can at least add on to Mike's suggestion. While the AAVSO database does not list the latitude of observers, perhaps someone can develop a tool that takes the home countries of active observers (perhaps over a year) to estimate what percentage of active AAVSO observers are likely to be at different latitudes. This could then be combined with a second tool that determines what percentage of AAVSO observers could see any specifed source above an airmass of 2 during a given evening.
Once again, thanks for the feedback.
Sincerely,
Greg Sivakoff
University of Alberta
I am on SS Cyg, it is around V mag 8.7. Will be back with more precise data in about one hour.
Finally I got close to two hours of observations (160 images), which is summarized on the attached graph. The average V mag is around 8.75. I have also uploaded 3 data points via WebObs, I understand it is not necessary to send in the whole series.
Hi Whit,
SS Cyg is keeping us guessing as to exactly what is going on. It looks like an anomalous outburst is underway - one in which the rise time is very slow (and about equal to the decline time). These anomalous outbursts don't happen often. We thought it might be a 'hiccup' in which SS Cyg rises some but then goes back down, but it doesn't really look like that now (although we haven't ruled it out completely). Please keep on observing SS Cyg and reporting your observations to the AAVSO as soon after you make them as you can.
Many thanks and good observing,
Elizabeth Waagen, AAVSO HQ
Elizabeth,
I am doing a short series on SS Cyg. Preliminary estimate put it at around 10.5. A more precise lecture in about one hour.
I just completed a one hour series of SS Cyg. While the brightness fluctuated slightly, there is a net tendancy to increase. She went from V mag 10.072 to 10.023.
It is quite unfortunate that SS CYG is not currently visible from Hawaii, but it is well above the horizon at morning twilight at my latitude (44 N). Unfortunately it is also low enough to be in the trees, but other observers (besides Damien) may find it to be within view soon.
Frank
I agree with the previous mesure.
My visual estimations were 8.70 yesterday evening 15/2 19h20 UTC and 8.75 this morning 16/2 5h00 UTC, all uploaded on WebObs
Michel DMIB
SS Cyg is due for an outburst in the coming week or so (if it's behaving fairly normally!). The radio campaign underway (it started in February) depends entirely on prompt notification of outburst onset by AAVSO observers - please see AAVSO Special Notice #414 for information from PI Dr. James Miller-Jones and for observing instructions.
Many thanks and good observing!
Elizabeth Waagen, AAVSO HQ
Hi Elizabeth and All,
UBV obs taken within the last hour indicate, in particular, that the U-Band light and the U-B index have both increased substantially compared with obs reported for Apr 3.43 and Apr 5.49 UT 2016. KIndly refer to the latest AAVSO observations page for SS Cyg. Thanks.
Steve
I believe that SS Cyg is just starting its outburst. It increased 0.3 mag since my observation 24 hours ago. In a 10 min period this morning in brightened 0.2 mag. Clouds rolled in and I could not continue so hopefully someone in the west can continue monitoring.
Barbara
Dear AAVSO observers,
First off, as one of the scientists involved in this campagin, thanks for the great job you are already doing. Your efforts are always incredible!
Dr. Miller-Jones and I have been keeping a close eye on the evolution of the source indicated by your data (since we are separated in time zones by nearly a half day, this gives us 24 hour coverage monitoring your data). There are both short term and a slightly longer term (since ~ beginning of April) indications that the source may be going into outburst soon, but it's not 100% clear yet that the outburst has started. We are thus on a very high alert, and will keep you all updated on the progress of our observations at other wavelengths when we trigger them.
Given our high alert status, I highly encourage you to upload your data as soon as possible, especially any data that you have taken over the past 12 hours or are planning to take in the near future. Your support is critical for our success!
Thankfully yours,
Greg
Gregory R. Sivakoff, PhD
Assistant Professor of Physics
University of Alberta, Edmonton, AB
sivakoff@ualberta.ca
Hi All,
As of Apr 14.45 UT (jd 492.95), the UBV colors and overall magnitudes strongly suggest the system is not yet in outburst.
Steve
It was quietly burbling along at 12.0 visual the night of the 12-13
Good Morning Everyone,
As of about one hour ago SS Cygni's UBV colors and relative magnitudes indicate no outburst yet. Observations submitted for April 15.4 2016 UT.
Steve
Hi All,
Attention ! Looks strongly like the anticipated outburst is set to go !
SS Cyg 11.68V (0.03) at Apr 16.4446 UT.
Regards,
Steve
Hi All,
Even though the V mag was reported relatively brighter at Apr 16.44 UT, the B-V color remained unchanged (near +0.58) compared to the day before. So not bluer and not yet in outburst !
Steve
Just observed it visually at 14:50 UT and it was varying a bit between 11.65 and 12.0, average about 11.8 so I don't think its going to outburst right now.
Mike LMK
Hi All,
Yes Mike, I had a look at it earlier today as well, at April 17.41 UT, the U-B color still near -0.3 and the B-V still near +0.6. The V mag was still down at 11.76. Still waiting for 'it'.
Steve
I made SS Cyg as mag 11.2
Hi,
I made SS Cyg as mag 11.2 visually (2016 April 18 at 08:19 UT).
John
Hi All,
The probable outburst report by ONJ is confirmed:
SS Cyg at 11.78TB and 11.22TG at April 18.424 UT.
Will try and get another obsn before dawn (SRO) to give you rate of rise.
Update: 2nd series not possible due to technical reasons.
Steve
11.125 V mag and rising at 12:39 UTC this morning...
My time series this morning showed it more or less steady up until 11:00 UT.
Dear AAVSO Observers,
On behalf of Dr. James Miller-Jones and our team, I wanted to inform you all that we have triggered our multi-wavelength observations of SS Cyg, based on AAVSO data. Below I update you all on our plans. As per the earlier notice, continued visual and CCD/DSLR (particularly V) observations are requested until SS Cyg reaches quiescence again.
Although there is a small chance that the source is undergoing a precursor hiccup, as seen in November 2015, we have triggered our radio and X-ray campaigns. Beginning April 19 (and continuing until the end of the outburst), we will be monitoring the radio emission of SS Cyg with AMI-LA (the Arcminute Microkelvin Imager Large Array) for at least 10 hours a day (when the source is visible from this array in Cambridge, United Kingdom) to measure what we believe is emission from a jet of particles moving at relativistic speeds. On April 19, the source will be visible at AMI-LA from 02:47-12:47 UT, and we may be able to get an extra hour of coverage on either or both sides of this window. Of course, this observing window will slip 4 minutes earlier in UT every day of the outburst
In addition to this dense radio coverage, we will observe the source three times (for twelve hours each epoch) with e-MERLIN (Multi-Element Radio Linked Interferometer Network), which has more sensitivity and better angular resolution than AMI-LA. With these observations we hope to determine if there are resolved ejecta associated with this jet. We will update this thread with the planned times of the eMERLIN observations as they get finalized.
Earlier today we were approved for two series of Swift X-ray Telescope observations to connect the inflow of material that feeds the outburst to the radio emission. The first series will be taken ~3 times a day during the rise of the outburst (April 19-21). The second series will be taken ~2 times a day during key portions of the decay of the outburst. As the telescope planners schedule the observations, those times should be updated online, but we warn observers that Swift is a telescope whose schedule can be strongly impacted by transient sources, even after the observations have been planned.
Throughout this outburst AAVSO continuing observations will play a critical role for four goals: confirming the source is indeed in outburst; triggering the eMERLIN observations based on the peak of the outburst; triggering the decay phase observations; and correlating the optical data with the radio data. Even if you can not take data that would be simultaneous with our other multi-wavelength data, your data is important! We recognize that SS Cyg is an early morning source for ground-based optical observations, and appreciate your efforts.
Thankfully yours,
Greg
Gregory R. Sivakoff, PhD
Assistant Professor of Physics
University of Alberta, Edmonton, AB
sivakoff@ualberta.ca
Greg,
Would it be worth doing time series, or an estimate once a day sufficient?
Damien
Hi All,
With the outburst now fully underway, I found the following at Apr 19.47 UT:
V=8.84 (U-B -0.41, B-V= -0.06)
kind regards,
Steve
Hi All,
Thanks to all the observers who have made it clear that we're in outburst (and in a particularly rapid rise).
First, let me answer Damien's question about whether we want time series or an average. In my opinion, this depends on two things: if you happen to be observing during between ~ 01 and 14 UT, time series may be useful for comparison with the radio of X-ray data; if you happen to see some dramatic variability, then I always suggest reporting such data. It is always possible to average data after it has been reported.
Second, below I update you on what observations we have managed to get scheduled.
AMI started observing earlier today (April 19) and will continue to do so until quiescence.
We were pleasantly surprised to find out the e-MERLIN took the first of four epochs of data earlier today as well. The powers that be did an amazing job to get on telescope a day earlier than we expected and granted us an additional epoch due to a receiver issue on one of their telescopes. The second epoch of e-MERLIN will be taken tomorrow (April 20) from ~ 1:40 - 13:40 UT.
The telescope operators at Swift also did an amazing job getting on source with three epochs today (April 19) 08:35 - 08:44:35, 10:10 - 10:19, and 11:35 - 11:44 UT. Three observations are already tentatively scheduled tomorrow (April 20) for 05:13 - 05:24, 06:46-06:58, and 11:35 - 11:47 UT. We also expect the last three epochs of the rise data to be taken on April 21.
Clear skies everyone!
Thankfully yours,
Greg
Gregory R. Sivakoff, PhD
Assistant Professor of Physics
University of Alberta, Edmonton, AB
sivakoff@ualberta.ca
Greg,
I made a short serie on SS Cyg this morning, it was stable close to 8.79 in V. Data have been uploaded to the AAVSO
Damien
Hi All,
Thanks for the continuing observations.
There's a hint from your data that we may be entering the decay phase of the current outburst of SS Cyg. As identifying the beginning of the decay can be quite difficult, I am not 100% confident of this interpretation. Your observations over the next few nights will be particularly critical in determining if the decay has begun and in helping us plan the last portion of the campaign.
Clear Skies,
Greg
Gregory R. Sivakoff, PhD
Assistant Professor of Physics
University of Alberta, Edmonton, AB
sivakoff@ualberta.ca
Dear SS Cyg enthusiasts,
AMI (radio) continues to monitor the source when it is visible from Cambride, UK.
It looks like eMERLIN (radio) was able to squeeze in an epoch earlier today that I thought would have occurred tonight; if I had known that they were going to be able to do that earlier, I would have let you know. The final eMERLIN epoch is likely to occur on the 27th or 28th. The eMERLIN staff will let us know more closer to the observation.
We have triggered the decay epochs of the Swift X-ray observations. The first two are scheduled for 2016-04-26 03:12-03:21:00 UT and 2016-04-26 10:57-11:06 UT. The next four will likley be scheduled, two per day on the 27th and 28th, between 2:20 and 12:20 UT.
Clear Skies,
Greg
Gregory R. Sivakoff, PhD
Assistant Professor of Physics
University of Alberta, Edmonton, AB
sivakoff@ualberta.ca
Dear SS Cyg enthusiasts,
AMI (radio) monitoring of SS Cyg ended today.
On behalf of the scientific team I want to thank you all for monitoring this particular outburst. Your help was absolutely essential. As we reduce the data and start to understand what we have observed at all wavelengths, I will try to keep you all in the loop by adding updates to this thread.
Clear Skies,
Greg
Gregory R. Sivakoff, PhD
Assistant Professor of Physics
University of Alberta, Edmonton, AB
sivakoff@ualberta.ca
Thank you Greg to keep us updated. I really appreciate this,... here why:
I made 57 visual estimations between Feb 5th and April 26th and trust me, no one was made from my backyard because of the lack of horizon. So that means that each night I take my car at 4 in the morning to reach a good spot to make the job. And thanks to your campaign I really enjoyed doing this.
To push more amateurs in my country to follow this type of campaign, I’m in the process of writing a paper for a French scientific magazine for astro-amateurs. So you understand that your feedback is very useful to me.
Thanks again to keep us up to date
Michel
Hello Michel
Thank you for your dedication and hard work on this campaign. Hope you enjoy the next one as much.
Gary
WGR
I agree with Gary, Michel should be congratulated on his hard work and dedication. He has set an admirable example for all of us. Keep up the good work!
- - Conan
MCOA