[ASA] Veloce Community Science Verfication:- Call for Proposals

Chris Tinney c.tinney at unsw.edu.au
Mon Jul 17 12:26:17 AEST 2023

Call for Community Science Verifiction Proposals
with Veloce Rosso+Verde+Azzurro

Due: Mon August 14
To: c.tinney at unsw.edu.au<mailto:c.rinney at unsw.edu.au>

The AAT Director has allocated the nights of August 24-30 for
Community Science Verification observations with the recently
installed 3-arm Veloce facility.

This Call for Proposals seeks community requests for science
programs using the new spectral range capabilitiies of Veloce.

It is particularly envisaged as a avenue for those considering new
programs using Veloce to obtain example data - e.g. to test whether
the new blue-green wavelength range provides coverage and S/N suitable
for your science goals on [insert your favourite class of object here],
in advance of the 2024A AAT proposal deadline.

Observations will be implemented by members of the Veloce team,
and raw data distributed immediately after the observing run. Extracted
data will be distributed as soon as the existing Rosso extraction system can be
extended to the Verde and Azzurro channels.

Background: The  three arms of Veloce provide complete wavelength coverage
at a spectral resolution of R=80,000 from 390nm to 930nm :
Azzurro channel: 391-431nm (in echelle orders m=157-142)
Verde channel:   590-431nm (in echelle orders m=142-104)
Rosso channel:  590-930nm (in echelle orders m=104-65)

The Rosso channel, echelle grating and fibre feed remain
unchanged from the system first installed in 2019. This
means all three arms are fed by the same 19-element IFU
at the AAT’s f/8 Cassegrain focus, collecting
light from a 2.5” diamater aperture for a single object.

The detector controllers have been upgraded with new
ESO NGC  (Next Generation Controllers), the performance
of which has (to date) been outstanding, with read noise
robustly <3.5e- per pixel to date and very flat bias/overscan
performance. There is now no-interquadrant detected
in Veloce and no substantial residual images from saturated

Expected Performance: Unfortunately, the first comissioning run
(June 28-July 2) was a complete wash out (the dome was not
opened on any of the 5 nights!). As such, while the designed
spectrograph resolution and detector performance has been verified,
detailed throughput for the new channels using on-sky targets
has not been measured. (An image of all three cameras being
read out is attached below).

From the examination of flat-field counts in the overlapping orders
between the Rosso and Verde channels, it appears that performance
for Verde and Rosso will be very similar. So proposers can extrapolate
time estimates for Rosso<https://protect-au.mimecast.com/s/j8L6Cr81nytrNl62Bs78knL?domain=docs.google.com> to Verde, and these should be about right (to
within a factor of 2).

Throughput for the Azzurro channel is much harder to estimate in advance.
All available continuum light sources have an intrinsic flux that plunges
steeply <450nm). And the fibre-feed throughput is expected to degrade in the UV.
For the time being, proposers are suggested to limit targets to B/V<10 at wavelengths
of 450nm or shorter.

It is expected that Community Science Verification programs will largely
focus on non-radial-velocity science with the newly added wavelength
range. Extracting radial velocity data from the Verde channel is expected
to take significant development over the new 6 months, so those results
can not be turned around quickly. (The Azzurro channel is not designed
for radial velocity science in mind at all).

Non-radial-velocity data (on the other hand) should be extractable quite quickly,
and so could inform proposals to use Veloce for the 2024A round of ATAC applications.

We will attempt to implement at least some observations from each program
received. If the total request exceeds the time available, a clear prioritisation
within your target list will be essential.

To Submit: Please send a 1 page (or less) description of your science
program to c.tinney at unsw.edu.au<mailto:c.tinney at unsw.edu.au> : including a list of targets observable
at the AAT in late August, S/N requirements at your wavelength of interest,
approximate etimates of exposure times, and a prioritisation for observations in your
target list. Try to aim for 0.5-1n of suggested observations per program.  If over-subscribed
we will try to get some data for each program, so make sure your priritisaiton
is clear. Our observer will adjust the exposure time to achieve your stated S/N


Chris Tinney
(for the Veloce team)


Professor Chris Tinney (he/him) | +61 416 092117 | skype:cgtinney | https://protect-au.mimecast.com/s/Q_gbCvl1rKiEBz4AkiXcn_3?domain=phys.unsw.edu.au<https://protect-au.mimecast.com/s/Q81dCwV1vMfvO3Pywi9WfCN?domain=phys.unsw.edu.au>
Exoplanetary Science at UNSW. School of Physics | c.tinney at unsw.edu.au<https://protect-au.mimecast.com/s/Gf7_CxngwOfLGoBxWIwY8ve?domain=unsw.edu.au> | Still living at work …

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