Forum der Vereinigung der Sternfreunde

Hello all,

Here are my test spectra for WR134/135
C11 (280mm)
LHIRES III 1200l/mm 35um slit
ATK 314L+ (2x binning)

resolution 1.3A
SNR 160 in 1 hour
wavelength precision ~5km/s

As I suspected, I cannot quite reach the specification from my sea level observatory. I would need ~0.5m aperture. If this quality useful however I can contribute to the campaign next year.

Cheers
Robin

This is excellent, Robin! We can always try binning later in the time domain. But then it just might be adequate. I had put rather stringent constraints to shoot for, knowing this would be a challenge. But when you come so close like this, then that will be fine.

Best regards, Tony

_________________
Tony Moffat

Hello Robin,

My great compliment to these spectra, you are the graetest.

Cheers berthold

Thanks Berthold,

I was quite pleased but I suppose the question is are they good enough? (Tony?) 280mm aperture might be enough on a mountain top but at sea level I am struggling to meet the spec. The resolution is lower than the 1A specified and I will need more than 1 hour to get the specified 200 SNR

Cheers
Robin

hello Robin,

my spectra are very poorly (correct?.. )against your spectra. I dont't understand why.......I used a grating with 1800 lines, but I don't think, that this is a logical explanation.......and you used an other wavelength range, but I think , this also is no reason , I could accept.......the KAF 1603 , I think, has a better QE at h-alpha than your Atik.......so I have no idea for what my spectra are so poorly........I have a little chance........I could use my C14, but also, I have to repeat, I don't believe, that this will help me........perhaps a can test it.......

cheers

berthold

Hello Berthold
I have some ideas which might help

1. Try moving to the wavelengths to be used for the campaign. It should be better at the shorter wavelength compared with H alpha because:

The grating is more efficient (closer to the blaze wavelength)
The continuum is brighter (WR stars are hot) so the SNR is better

2. Try binning x2 (this should be perfect with a 35um slit and your 9um pixels)

Using the C14 should also help

Good Luck!
Robin

Thank you Robin, I shall try it this night!


Cheers Berthold

Von meinem iPad gesendet

Am 08.09.2012 um 13:38 schrieb Robin Leadbeater <fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)>:

helleo Robin,

after having done exactly as you said, now.....now I have also a somewhat usefull result, I think......my spectrum is not so good as yours but it is of comparable quality in my eyes. What do you mean?


So I hope and I think that I can reache an exp. time from 60 min. , if I use the C14.......then all the given conditions are considered......

cheers berthold

the weather here becomes bad for the next days....

(PS : the accuracy of callibration is not so good, as I see.....I have to use sms in the next days)

Hi Robin, your stuff is excellent. I believe it is fine for the campaign. Go ahead!

Thomas

Hi Robin,

it´s so nice to see some spectra here and even more so, beeing of such great quality.

One question: How long was the average exposure for each frame?


Cheers,
Torsten

Hello Berthold,
To me, it looks like a great improvement.


Cheers
Torsten

Thanks Torsten,

Theory is OK but in the end you have to test yourself against the real world

The WR134 exposures were 20min each but for WR135 I had to reduce this to 5min to stop the very strong emission line saturating.

Cheers
Robin

Here is the WR134 HeII 5411A line taken 20120911

Exposure was 30 min (limited by clouds) SNR 120 resolution 1.3A
wavelength was calibrated using Ne and Ar lines in LHIRES internal neon lamp

5330.778 Ne
5400.562 Ne
5421.352 Ar
5451.652 Ar
5495.874 Ar

A second order fit gave an RMS residual of 0.03A

Next step is to repeat this to see if variations can be detected

Cheers
Robin

Exzellent Robin!

so far in the blue part of the spectrum I have no calibration lines in my lhires. I have only a neon lamp in my lhires.....the sky here is cloudy at time....

Cheers Berthold

Hello Berthold

There is also a small amount of Agon in the Neon lamp but the lines are very weak in this area (<1% compared with the strong Neon line at 5400A) and there are many other unknown weak lines so you need to take care. These ones seem to work for me though.

Cheers
Robin

A comparsion of my recent spectrum with one from Thierry Garrel last year. The spectra have been approximately normalised based on the "continuum" regions immediately either side of the line. The changes on the top of the line are very obvious

Cheers
Robin

Wow! That looks excellent, Robin. You certainly match our needs... with a C11. Impressive. Congratulations! Keep going as often as you like and keep all the spectra for the campaign. And then mid May: FIRE untill September.

Cheers, Thomas

My congratulations go to Thierry, as well, of course. Great work from both of you, guys.

Here is a series of 20min exposures covering 3 hours on 20120918
The SNR is ~100 in each exposure. There are obvious changes on the line top even over this short time, particularly on the red edge.

Cheers
Robin

Hi Robin:

Looks very nice. However, I think you need a bit more S/N to get rid of the short-scale noise that could prevent clear detection of clumps. That?s why I had said S/N about 200, although 160 may be OK in 1 hour.

Best, Tony

From: Robin Leadbeater (fg-spek-convento@vds-astro.de)
Sent: Wednesday, September 19, 2012 9:08 PM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: WR134,135 test results fromThree Hills Observatory




Robin Leadbeater wrote:
Here is the WR134 HeII 5411A line taken 20120911

Next step is to repeat this to see if variations can be detected


Here is a series of 20min exposures covering 3 hours on 20120918
The SNR is ~100 in each exposure. There are obvious changes on the line top even over this short time, particularly on the red edge.

Cheers
Robin

_________________
Tony Moffat

Hi Tony,

Yes these are just the sub exposures that will go to make 2 spectra of 1 hour exposure each. I was interested to see however that significant changes were detectable at 100SNR and even within < 1 hour. Attached is the same spectra overlaid showing how the envelope widens at the red edge of the line compared with elsewhere.

Cheers
Robin

Great Robin , indeed very good work


Berthold


Von meinem iPad gesendet

Am 20.09.2012 um 04:26 schrieb Robin Leadbeater <fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)>:

Hi Robin, Tony!

The whole line seems to be slightly shifted towars larger wavelenths. What might that be?
Second, clumping should be visible all over the line peak. Here we see variability only in the red peak whereas the blue side is more or less stable. I miss the outward moving sub-features.

Thomas

Here is my previous result from 20120911 overlaid on the first and last spectra from 20120918

Cheers
Robin

Hm, we probably need much more data to identify specific phenomena. Clumping is visible within minutes to hours. So, the single night observations should also show blue wing activity. But the absence might be a stochastic effect (or CIR activity). Too difficult to say with only some spectra. Anyway, your observations obviously show what you can already do with a C11. It is at our parameter threshold but it works.

Cheers, Thomas

Hi Thomas:

WR emission lines tend to be redshifted (it?s part of the line-formation mechanism), sometimes by over 100 km/s. Plus the star could be moving at some positive speed relative to us.

WR134 is dominated by quasi-periodic CIR motion, so the clumps play a secondary role, although they should still be visible. Perhaps one also needs a longer data string (i.e. more than 3 hours; 6+ better). See http://iopscience.iop.org/0004-637X/514 ... 60.web.pdf Fig.1.

We should also compare WR134 with WR135 and WR137 (also in the above paper, but for WR135 see also the best spectroscopic paper ever on any clumped star: http://iopscience.iop.org/1538-3881/120 ... 56.web.pdf . Here we have 3 intense successive nights on two 4m class telescopes (WHT, CFHT, with some cloudy periods!). This is great of course, but we need much longer time coverage to build up better statistics of the clumps and check for a hidden periodicity (e.g. due to weak CIRs), so that?s why we launched this 4-month campaign. But it is important to get adequate coverage each time one observes each star, i.e. at least 4-5 hours with at least 3 good spectra (S/N > ~200). But preferably all night for over 6 hours with even more good spectra, when possible. That?s also why it would be good to have people spread around the globe doing spectroscopy, to fill in the time gaps that one gets from only one site.

Cheers, Tony


From: Thomas Eversberg (fg-spek-convento@vds-astro.de)
Sent: Thursday, September 20, 2012 3:23 AM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: WR134,135 test results fromThree Hills Observatory




Hi Robin, Tony!

The whole line seems to be slightly shifted towars larger wavelenths. What might that be?
Second, clumping should be visible all over the line peak. Here we see variability only in the red peak whereas the blue side is more or less stable. I miss the outward moving sub-features.

Thomas

_________________
Tony Moffat

Very nice, Robin! The changes are quite evident, while the line flanks remain ~ constant.

Tony

From: Robin Leadbeater (fg-spek-convento@vds-astro.de)
Sent: Thursday, September 20, 2012 6:30 AM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: WR134,135 test results fromThree Hills Observatory




Here is my previous result from 20120911 overlaid on the first and last spectra from 20120918

Cheers
Robin

_________________
Tony Moffat

Clumps can show changes over 10?s of minutes, not minutes. But you really don?t see much happening normally until you wait for about an hour. There are some exceptions, though, e.g. weak emission-line stars where we see the fast-accelerating inner part of the wind.

Also: some lines show little if any P Cygni absorption edges, so their extra blue-wing activity is absent.

Tony

From: Thomas Eversberg (fg-spek-convento@vds-astro.de)
Sent: Thursday, September 20, 2012 7:08 AM
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Subject: [fg-spek] Re: WR134,135 test results fromThree Hills Observatory




Hm, we probably need much more data to identify specific phenomena. Clumping is visible within minutes to hours. So, the single night observations should also show blue wing activity. But the absence might be a stochastic effect (or CIR activity). Too difficult to say with only some spectra. Anyway, your observations obviously show what you can already do with a C11. It is at our parameter threshold but it works.

Cheers, Thomas

_________________
Tony Moffat

Excellent Robin!


Berthold


Von meinem iPad gesendet

Am 20.09.2012 um 12:30 schrieb Robin Leadbeater <fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)>:

Hi Thomas et al.:

This is just to say that I have written letters to various professional groups asking them to join the campaign to observe WR134, 135 and 137 next summer (2013 June-Sept). These include so far:

Juan Zorec (OHP ? he has already answered that he would like to join and submit an application to OHP, the observatory that provided very nice data for WR140 last time)
Laura Penny, CoC
David Bohlender, DAO
Grant Hill (Keck)
Jon Bjorkman, U. of Toledo & Ritter Obs.
Doug Gies, GSU


We will continue asking any others whom we think appropriate, but we are also open to any ideas.

Also, we are looking into who might take charge of coordinating all the data and I am confident that we?ll find someone, probably at UdeM.

Cheers, Tony

_________________
Tony Moffat

Hello Robin and all others

here my result from 300613 of WR135,

cheers berthold