From jop at astro.columbia.edu  Wed Jan 11 15:28:51 2017
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 11 Jan 2017 15:28:51 -0500
Subject: (cba:news) T Pyx, finis; CN Ori, maybe ditto;
 CP Pup, Paloma, FS Aur, BY Cam
Message-ID: <ef341c09-f8eb-03e9-c3da-08ab758a4702@astro.columbia.edu>


Dear CBAers,

Our long infatuation with T Pyx should go into hiatus now.  The paper 
has been finally published (attached), and the new timings for this year 
are consistent with the posteruption ephemeris.  So the time-keeping for 
the orbital signal is established for the rest of the observing season.

As I think you know, David Boyd's paper on DW UMa is also slated for 
publication in MNRAS, and Gordon Myers' paper on CD Ind in PASP.  And I 
think Enrique's paper in MNRAS on RX2133+51 is about to get the blessing 
(or maybe already has).  A good end of 2016.

If you like CN Ori, keep up the coverage for another week or two; but we 
have some very dense coverage and no longer need all hands on board.

CP Pup, however, could definitely profit from all hands on board.  Our 
last campaign strongly suggested that the star's big superhumps occur at 
a period *much* longer than Porb.  We need to investigate this!  Our 
supply of southern observers is not vast, but the quality is high, and 
with sufficiently *dense* coverage (all-night runs at more than one 
longitude), we could well resolve this.

Paloma (RX J0624+42), FS Aur, and BY Cam are other stars which we should 
nail before their observing seasons get away from us.  We have 
ephemerides, but they need bolstering/confirming with good Jan-Feb coverage.

Finally, I'm looking for some good Mac-compatible software for period 
analysis, plotting, etc.  Can anyone advise me on this?

joe
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From jop at astro.columbia.edu  Thu Jan 12 18:46:36 2017
From: jop at astro.columbia.edu (Joe Patterson)
Date: Thu, 12 Jan 2017 18:46:36 -0500
Subject: (cba:news) HT Cas
Message-ID: <5d5f319c-6c48-4c26-2fcc-5adadf81b7f4@astro.columbia.edu>

As many of you know, HT Cas is in superoutburst.  Definitely a great 
target for northern observers!

joe
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From jop at astro.columbia.edu  Wed Jan 18 05:59:36 2017
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 18 Jan 2017 05:59:36 -0500
Subject: (cba:news) Tis the season for YZ Cnc
In-Reply-To: <1ACF80922713204BA703D6242931D16354C41B26@SRV00048.soton.ac.uk>
References: <1ACF80922713204BA703D6242931D16354C41B26@SRV00048.soton.ac.uk>
Message-ID: <720b10d0-88d9-81ca-766d-269896f7d32b@astro.columbia.edu>

Hi CBAers,

Let's promote YZ Cnc to a high-priority star.  While the main motivation 
is to document the nightly light curve in preparation for a triggered 
X-ray observation, the star has also been (oddly) overlooked for dense 
coverage of quiescent and eruption light curves.  It's the season for 
very long runs.  Let's stitch them together and search the light curves 
for those strange not-quite-orbital periods which are our specialty!

joe


-------- Forwarded Message --------
Subject: YZ Cnc
Date: Wed, 18 Jan 2017 06:16:05 +0000
From: Knigge C. <C.Knigge at soton.ac.uk>
To: Joe Patterson <jop at astro.columbia.edu>

Hi Joe,
is there any way you could request extra dense monitoring of YZ Cnc from
the CBAers until further notice? I'd really like to trigger asap, but
coverage has become pretty sketchy -- I'd really like to catch it on the
rise!

Thanks!

Christian


-- 
===================================================
Professor Christian Knigge
Physics & Astronomy
University of Southampton
Southampton SO17 1BJ
====================================================

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From jop at astro.columbia.edu  Wed Jan 18 06:22:35 2017
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 18 Jan 2017 06:22:35 -0500
Subject: (cba:news) Further on YZ Cnc...
Message-ID: <8c285c7c-c6d4-e81d-53e3-6d63f2eb8727@astro.columbia.edu>

In order to trigger the X-ray observation, we need to identify (or 
accurately predict, if that be within your powers) the start of an 
outburst.  If you observe it regularly every night, and also study the 
AAVSO records to see what others have done, you're likely in the ideal 
position to make that prediction.  It probably won't be a super (one 
occurred around Xmas), but the normal outbursts count too.  So... 
observe it closely, study the pattern of the normal outbursts to see if 
you can get a feel for when the next one is, and send to cba-chat or 
cba-news so other observers, perhaps at other longitudes, can weigh in.

There has never been a dwarf nova with full beginning-to-end X-ray 
coverage of an outburst.  The big obstacle is knowing when the outburst 
happens, and the START is hardest of all (since there's plenty of 
irregular variability at quiescence).  But these things can be partially 
overcome by just *getting to know the star*.

And that would be you!

joe

p.s. I know that our australites are disinclined to cross into boreal 
regions, but short observations can contribute plenty to this. 
*Longitude* spread is really desirable in this matter.
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From jop at astro.columbia.edu  Wed Jan 25 11:03:20 2017
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 25 Jan 2017 11:03:20 -0500
Subject: (cba:news) YZ Cnc and the campaign
Message-ID: <bfdf971e-5d08-f7c3-a1d0-e15e42547a7b@astro.columbia.edu>

Hi CBAers,

They decided *not* to trigger the X-ray observation on the YZ Cnc 
outburst a few days ago.  All the pieces weren't quite in place.  Good 
chance on the next one though, possibly 4-8 days away (very roughly). 
So keep up the long time series.  Two other things that would be helpful:

(1) Post to cba-chat as well as cba-data.  That way, everybody gets it, 
and can study your data in conjunction with their own to form a judgment 
as to when the outburst is "beginning".

(2) If you're able to cover the star quite a bit, compare your data with 
that already in the AAVSO archive to make a guess about this.  Let us 
know your guess (through cba-chat); it's of much more value than those 
of us who, like me, just read emails!

(3) It's probably best if you submit actual magnitudes rather than just 
delta-magnitudes.  About half of CBAers customarily use 
delta-magnitudes, since they're, strictly speaking, more accurate.  But 
your magnitudes will be more *useful* if you add the magnitude of the 
comp star, or some known comp star.  And if you are very familiar with 
the field and have some particular comp star you favor, let us all know. 
  I think Enrique uses the AAVSO 137 star (V = 13.688).

That's true in general, also - that your estimate of actual magnitude, 
not delta-mag, is more useful.  In the time-series analysis, I usually 
subtract the mean anyway, so it doesn't corrupt anything - and it shows 
at a glance, though admittedly roughly, whether the star is in a "high" 
or "low" state.  V_comp + delta-mag is usually the best way to go.

joe p
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From jop at astro.columbia.edu  Wed Jan 25 16:36:24 2017
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 25 Jan 2017 16:36:24 -0500
Subject: (cba:news) YZ Cnc, oops, priority now changed
In-Reply-To: <1ACF80922713204BA703D6242931D16354C532AD@SRV00048.soton.ac.uk>
References: <1ACF80922713204BA703D6242931D16354C532AD@SRV00048.soton.ac.uk>
Message-ID: <318e040b-8c5c-0edc-4966-e2f28a7709b5@astro.columbia.edu>

Hi CBAers,

Just got this from Christian Knigge, who is organizing the YZ Cnc 
campaign.  The X-ray satellites have pointing constraints, which are 
mostly - but alas not entirely - predictable in advance.  Chandra can't 
look at that position for at least another 8 days. So demote YZ Cnc in 
priority until ~Feb 2.  It's still a decent target, but short-ish time 
series will do, since the idea (until dense coverage starts in February) 
is mainly to construct a detailed record of the
daily pattern of eruptions.

joe p


-------- Forwarded Message --------
Subject: Re: YZ Cnc
Date: Wed, 25 Jan 2017 20:41:00 +0000
From: Knigge C. <C.Knigge at soton.ac.uk>
To: Joe Patterson <jop at astro.columbia.edu>, jk >> Jonathan Kemp 
<jk at 155west.org>

I'm so sorry -- I've just been told by Chandra Mission Planning that,
actually, YZ Cnc is fully unobservable until at least Feb 5 and only
partially observable between then and Feb 11. They've apologized for not
saying this sooner, but of course I've already told all the amateurs to
help with dense monitoring -- grrr...

What that means in practice is that we really don't need data urgently
until about a week from now, say Feb 2 or so. After that, all the stuff
I said before is still true, i.e. really dense monitoring to catch the
early rise is critical.

Cheers,

C




On 24/01/17 15:16, Joe Patterson wrote:
> Thanx.  With that description, I'm going to encourage them to keep
> getting long time series.  That will give them a decent baseline from
> which to judge rises in light (versus flickering).
>
> I don't understand "pre-confirmation"... but I don't think I need to.
> I'll ask them to submit data to cba-chat, so everyone can look at
> everyone else's data, taking advantage of the spread in longitude.  If
> you get cba-chat (JOnathan, can you add Christian in case he doesn't now
> get it?), you'll see it too.
>
> Buena suerte!
>
> joe
> On 1/24/2017 6:06 PM, Knigge C. wrote:
>> I'd really like to trigger on the very next outburst for which we have a
>> chance. That's important also for the GOALS project itself (since YZ Cnc
>> is one of the candidate targets for this), as the deadlines for this
>> round are coming up...
>>
>> In practice, a trigger will require (i) super-early notification from
>> the amateur community; (ii) confirmation from Chandra that the
>> turn-around they can provide if we do trigger will be good enough for
>> the science.
>>
>> (The second point is part of a special protocol we've got going with
>> Chandra that should help us avoid a trigger that just narrowly misses
>> outburst -- at the moment, the outbursts last only about 3 days, and the
>> normal trigger window we're approved for is 1-3 days. So with sufficient
>> bad luck, we could have been in trouble, but the informal
>> "pre-confirmation" should avoid this.)
>>
>> C
>>
>>
>>
>> On 24/01/17 15:02, Joe Patterson wrote:
>>> Do you expect to trigger on the next normal outburst, or one more after
>>> that... or?  If the next, I'll tell them to wait 5 days, then resume
>>> intensive coverage.  That make sense?
>>>
>>> joe
>>>
>>> On 1/24/2017 5:53 PM, Knigge C. wrote:
>>>> Hi Joe,
>>>>
>>>> sorry for not responding to your other email yet -- will do so asap
>>>> (really snowed under just now). For now, I wanted to send oeragen a brief
>>>> update on the YZ Cnc campaign that I just posted to the AAVSO and BAAVSS
>>>> fora, to make sure we get the dense coverage we need to finally trigger
>>>> that one. Not sure if this is worth sharing with the CBAers or not...
>>>>
>>>> Thanks for all your help with this!
>>>>
>>>> Christian
>>>>
>>>> =======================================================================
>>>>
>>>> Hi all,
>>>>
>>>> I thought I'd provide a brief update on the campaign, mainly to say
>>>> thanks for all the help so far and also to beg for continuing -- ideally
>>>> even denser -- coverage.
>>>>
>>>> For our Chandra ToO observations, we need to catch YZ Cnc somewhere near
>>>> the peak of a normal outburst. This is obviously quite difficult, given
>>>> how short they are. I *almost* triggered on the first normal outburst
>>>> after the last super, but it turned out I was in transit from the UK to
>>>> the USA at exactly the time I would have had to be doing this. Murphy's Law.
>>>>
>>>> In any case, in order for this trigger to work, super-early notification
>>>> of the start of an outburst is critical. Only amateur astronomers will
>>>> be able to provide that for us. We have a special protocol in place with
>>>> Chandra that will hopefully ensure that our trigger is successful, but
>>>> it really rests *crucially* on that early notice. So really dense
>>>> coverage of the rise and early notifications are central to our entire
>>>> program.
>>>>
>>>> Again, thanks to all who have already contributed, but please keep going
>>>> -- the campaign is still going, and I will definitely let you know once
>>>> we have triggered and we are done. In the absence of such a note from
>>>> me, you can assume that we have not yet been able to find trigger the
>>>> X-rays early enough, so our attempt to get this will continue until we do.
>>>>
>>>> I am really grateful for all your help -- campaigns like this would be
>>>> impossible without you!
>>>>
>>>> Cheers,
>>>>
>>>> Christian
>>>>
>>>> ========================================================================
>>>>

-- 
===================================================
Professor Christian Knigge
Physics & Astronomy
University of Southampton
Southampton SO17 1BJ
====================================================

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