Rob
I have taken simultaneous photometry on the 2 nights I have taken spectra. The data for B and V have been uploaded to AAVSO. I took R and I data last night as well but I don't have comp data in those bands. Hopefully it will appear in the future.
Terry
Nice to see our B and V sitting nicely within 0.02-3 mag of each other.
It would be good for the AAVSO guys to provide a bit more comp data about now ...
Glad to see all this data coming together!
Steve Shore has asked for all data to be uploaded (BeSS fits format) to the ARAS forum for further discussion. He's also suggested recording the line velocity profiles for various emission lines......details to follow.
Rob
I have taken simultaneous photometry on the 2 nights I have taken spectra. The data for B and V have been uploaded to AAVSO. I took R and I data last night as well but I don't have comp data in those bands. Hopefully it will appear in the future.
Terry
Excellent Terry, I kind of suspected you might have it all in hand!
Leaving the data in wavelength masks important information. Put
instead, in velocity, you convert the profile into a map of the ejecta.
In the sense that the radial velocity depends on radius, for fixed
orientation relative to the observer, the higher velocity parts of the
profile are from the outer portions of the ejecta (this would be true
for a wind too, as in a classical P Cyg profile).
By doing this you also can compare profiles of different ions,
for instance seeing how the Balmer lines change (which is the same ion,
neutral hydrogen) or the changes in the resonance line of Na (the D
lines) compared with [O I]6300, say, which is a forbidden line and
traces lower density gas.
Once you've done this simple step you start to see a lot of the physics,
and the time dependence starts to make sense because you can
compare across excitations and ionizations.
Try comparing Halpha and Hbeta, that's the simplest to get a feel for
the optical depth variations in the absorption component. There's also
a progression -- the H-beta absorption is at a lower velocity than
H-alpha because it's formed (from our point of view toward the ejecta)
further inside (in other words, you have to look geometrically deeper
to get the same optical depth). Then Na I 5889.95,5895.92, when it's
observable He I 5876, the multiplet Fe II 4923, 5018, 5169, and the O I
6300, 6364 doublet. When it's observable, N II 5755. These should be
a good start.
No, I've asked the question, but no comment as yet.
I'm about to change over to the 1200 l/mm grating see how that goes.
(I don't want to go to the 1800 l/mm at the moment...)
Malc et al,
At the moment they're just personal emails between Steve and myself - having said that I've no problem sharing....
I get the feeling he really want's to work through the ARAS forum - like he did for the Nova Del....
Let me know if you want copies of the current emails.....
This is his reply re the magnitude fluctuations:
"" The most interesting feature of the light curve, I think, is its
similarity to a few other classical systems (historical ones) that have
shown "oscillations" during the peak and early stages of decline. The
one that is rather striking is a relatively recent nova, V5588 Sgr
2009. It was quite faint, there are VERY few spectra, but the two
Christian managed to catch are similar to the V1369 Cen spectra now
and, more to the point, don't show any hint of Ne so it was likely a CO
type. The only spectra were from the optically thick stage (at least
the only ones I can see, Fred Walter has sequestered the others from
SMARTS although I';ve seen them, low resolution but enough to be
interesting in the optically thin stages). These oscillations, if you
extend the light curve to months instead of weeks, seem to increase in
their intervals. This was seen,. for instance, for GK Per 1901
although not realized at the time, and with the earlier optical
(visual) data you can never be quite sure. There were also multiple
peaks in other classical systems, CP Pup for instance, that were
actually relatively fast. And then there's T Pyx, everything odd a
nova can do was and is done by this one. But the interesting feature
of its light curve is that there isn't this same sort of quasi-periodic
behavior in the multiple peaks, they seem to come on a timescale but
not so nearly regularly.
What this is, at this stage, would require too much speculation. But
being a theorist by training, there are two clear possibilities (still
speculative). The thermonuclear source could still be exciting
ejections, but on this timescale it's very hard to believe unless it's
an indication of intermittent accretion, again something that's hard to
compute and harder to credit. Or there could be -- already -- a
thermal instability of the WD that's causing a variable illumination of
the ejecta as the effective temperature changes. This is more
reasonable, the timescales are kind of ling but not impossible, but
that's something I'm still working out. It's been suggested that after
the ejection event there is a relaxation of the WD so perhaps that's
going on here and the angle of viewing is favoring a view of the
phenomenon. The objection is that this is a rare thing, while other
novae would be expected to show it unless it's something specific to
the WD mass.
Anyway, these are still idle thoughts in the early stages. One should
remember that although the nova event is brief in normal astronomical
senses, the behavior is individual (even with regularities) and
patience is always a virtue.
I hope this helps. ""
We really need to organise/ arrange with Francois and the ARAS forum to collect and publish the data as well as a running commentary from Steve.
Thanks Ken. I find it interesting that he mentions:
" The most interesting feature of the light curve, I think, is its similarity to a few other classical systems (historical ones) that have shown "oscillations" during the peak and early stages of decline. The one that is rather striking is a relatively recent nova, V5588 Sgr 2009."
That one struck me as something unusual. It was quite dim (not reaching mag 11) and was in one of my usual nova search fields. I actually gave the alert on the second big spike through vsnet-alert because it suddenly became visible again in my frames. It disappeared again but later I seemed to get a faint trace of it again. Not entirely confident in what I was seeing, I did notify Mike Simonsen (AAVSO) who had been observing it - turns out it was the third spike! I posted the AAVSO light curve in the other thread a week or two back, link here: http://www.iceinspace.com.au/forum/s...&postcount=135
But you'll see it's not quite the same behaviour as V1369 Cen.
Thanks for these, Ken. Really interesting stuff from Steve.
Who here us a member of the ARAS forum? I've tried to register repeatedly but get nothing back from them. I've tried to email Francois about it but he doesn't reply. Any suggestions?
Who here us a member of the ARAS forum? I've tried to register repeatedly but get nothing back from them. I've tried to email Francois about it but he doesn't reply. Any suggestions?
No suggestions here Jon, I tried it too with no success.
Interesting stuff in your colour version, Rob. 5577, 5755 both clear. I wonder what's going on with the strong absorption line at about 561 Nm? It's showing up in mine of last night, too- much deeper than the previous night.
Who here us a member of the ARAS forum? I've tried to register repeatedly but get nothing back from them. I've tried to email Francois about it but he doesn't reply. Any suggestions?
One thing to be sure of is to use your full name as your username when you sign up. I tried to sign up with my usual username of malclocke and got nowhere. I think they maybe get a lot of spam sign ups. See http://spectro-aras.com/forum/viewtopic.php?f=16&t=31
Can't offer any advice on lack of response to emails though. François is certainly around as he has been posting to the forum and mailing lists.
Keep trying. I thought I was being stonewalled at first, but that was definitely not the case.
I'm also an ARAS member and had an email from Francois today after I sent him my latest spectra for the database. He is certainly around.
I don't remember a problem with joining up but it was a long time ago.
One thing to be sure of is to use your full name as your username when you sign up. I tried to sign up with my usual username of malclocke and got nowhere. I think they maybe get a lot of spam sign ups. See http://spectro-aras.com/forum/viewtopic.php?f=16&t=31
Can't offer any advice on lack of response to emails though. François is certainly around as he has been posting to the forum and mailing lists.
Keep trying. I thought I was being stonewalled at first, but that was definitely not the case.
Well, so far so good (I'm sure that's what the Captain of the Titanic said about 11:30pm!)
I've changed over to the 1200 l/mm grating
So far I've collected some Ha data and (hopefully) the Hb is being done as I type....
Let's see...
Hmmm
Now working at R=4040....
Could have done with more exposure time....
The Hb region is the first processed...showing the now "standard P-Cyg" in both the Hb and Fe lines.
I've run a velocity graph based on the Hb (4861A) showing the larger absorption is still around the 1600Km/s
Feedback/ comments welcome.
