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Request for spectrum asassn 20mg dec 48 south
Posted: Sun Oct 11, 2020 10:55 pm
by Hamish Barker
Possible galactic microlensing event for southern observers.
Bernard heathcote, terry bohlsen and other southerners, I would email you directly but don't have your address.
https://wis-tns.weizmann.ac.il/object/2020tyr
So far I got a rather poor slitless spectrum with star analyser 4x1200 s on a 200mm f6 newtonian, contaminated by zero order images at longer end ( Dropbox link with raw files here)
https://www.dropbox.com/sh/cfkllbs112xf ... eBdia?dl=0
- asas-sn-20mg-field.jpg (96.71 KiB) Viewed 6954 times
Clear again today after lots of rain so tom love and I will both be attempting observations with sa100 and alpy 600 respectively.
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Tue Oct 13, 2020 6:50 am
by Tom Love
I think the point of interest is that it was thought to be a microlensing event, but the curve now doesn't look much like that, so nobody is quite sure what it is...
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Tue Oct 13, 2020 10:31 am
by Terry Bohlsen
Hi Hamish
I’m currently taking a spectra with my LISA and V images also. I’ll post it here later.
Terry
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Wed Oct 14, 2020 9:22 am
by Peter Velez
I'm keen to see your results Terry
I'm imaging this at the moment. We can exchange notes
Pete
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Thu Oct 15, 2020 8:31 am
by Peter Velez
My data from last night were poor. Binning would have produced a more useful spectrum. Its so ordinary I hesitate to share.
Looking at it (squinting) I can make out Ha emission and absorption for H beta and H gamma. Looks blueshifted a bit - Ha at -132 km/s.
Will try again
Pete
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Sat Oct 17, 2020 2:19 am
by Hamish Barker
Here is my results from three nights (5th, 13th and 15th october). Total of 200minutes exposure with SA100 on 200mm f6 newtonian. S/N is pretty poor but better than nothing I guess. Should i upload to BESS?
I will be very interested to see Terry's results!
- 20mg-5-13-15-sum-4x1-bin.png (9.7 KiB) Viewed 6825 times
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Sat Oct 17, 2020 11:11 am
by Robin Leadbeater
Hamish Barker wrote:. Should i upload to BESS?
Hi Hamish,
It looks roughly like an F/G star from the continuum shape so not your typical CV or variable red giant. It could be a lensing event (The test for lensing is no change in the spectrum with brightness)
BeSS is only for Be stars. You could add it to the BAA database which accepts spectra of any astronomical object. Star Analyser spectra are accepted if they are of a unique event.
Cheers
Robin
EDIT just seen the light curve. I agree, not a typical microlensing curve
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Sat Oct 17, 2020 11:15 am
by Robin Leadbeater
Hi Pete,
Peter Velez wrote:
My data from last night were poor. Binning would have produced a more useful spectrum. Its so ordinary I hesitate to share.
Looking at it (squinting) I can make out Ha emission and absorption for H beta and H gamma. Looks blueshifted a bit - Ha at -132 km/s.
Will try again
Pete
What is the continuum shape like? how does it compare to Hamish's ?
Cheers
Robin
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Sat Oct 17, 2020 8:52 pm
by Hamish Barker
I saw on twitter that someone took a spectrum with the SALT but they were "still trying to work it out". no other details given.
Re: Request for spectrum asassn 20mg dec 48 south
Posted: Sun Oct 18, 2020 6:22 am
by Terry Bohlsen
sorry I'm slow getting this too you.
My spectra was taken with my LISA.
It is pretty noisy as it was low in the west when I took it.
The continuum is pretty flat. There is certainly Hb and Hg absorption and weak Ha absorption maybe buried in the noise.
Certainly there are no major emission lines anywhere.
Terry