Request for spectrum asassn 20mg dec 48 south

Request for spectrum asassn 20mg dec 48 south

Postby Hamish Barker » Sun Oct 11, 2020 10:55 pm

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/cfkllbs112xf8sk/AACDDDjul-jiotbeWUwpeBdia?dl=0

light_curve_cbc38ab0-d917-404f-b526-4ad6e34d0805.png



asas-sn-20mg-field.jpg
asas-sn-20mg-field.jpg (96.71 KiB) Viewed 1843 times



Clear again today after lots of rain so tom love and I will both be attempting observations with sa100 and alpy 600 respectively.
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Tom Love » Tue Oct 13, 2020 6:50 am

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...
-------------------------------------------------
Martinborough, New Zealand. Alpy, Lhires RC12
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Terry Bohlsen » Tue Oct 13, 2020 10:31 am

Hi Hamish
I’m currently taking a spectra with my LISA and V images also. I’ll post it here later.
Terry
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Peter Velez » Wed Oct 14, 2020 9:22 am

I'm keen to see your results Terry

I'm imaging this at the moment. We can exchange notes

Pete
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Peter Velez » Thu Oct 15, 2020 8:31 am

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
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Hamish Barker » Sat Oct 17, 2020 2:19 am

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
20mg-5-13-15-sum-4x1-bin.png (9.7 KiB) Viewed 1714 times
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Robin Leadbeater » Sat Oct 17, 2020 11:11 am

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
Last edited by Robin Leadbeater on Sat Oct 17, 2020 11:27 am, edited 1 time in total.
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Robin Leadbeater » Sat Oct 17, 2020 11:15 am

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
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Hamish Barker » Sat Oct 17, 2020 8:52 pm

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.
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Re: Request for spectrum asassn 20mg dec 48 south

Postby Terry Bohlsen » Sun Oct 18, 2020 6:22 am

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
asassn20mg_20201013_436_TBohlsen.png
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