Subject: echelle contributions

From: Donald G. York

Submitted: Thu, 8 Aug 2002 01:51:30 -0500

Message number: 599 (previous: 598, next: 600 up: Index)

I am submitting a proposal to NSF for an upgrade of the echelle, 
mainly the replacement of the 25 micron SITe CCD with a 15 micron 
device. Our current limits for data that is actually useful is about 
14th. This is lower than calculated from the data on flux calibrators 
because of radiation events. The events will be easier to remove.

I am seeking interesting projects from ARC astronomers to use as 
justification in the proposal. If you have something in mind, a 
paragraph or two would be appreciated, in the next 10 days. I will 
not use the material verbatim, but will merge it into connected text, 
with other projects. I will, however, mention names of those 
interested, unless you ask me not to.

Unfortunately, I cannot give you firm performance specs. We are 
modelling the spectrum of the radiation events to determine the 
revised limiting magnitude, which depends, additionally, on the read 
noise of an unpurchased and probably not yet constructed, CCD.

The throughput of telescope/spectrometer is about 2% at 6000A, 
constant from 38000A to 9000A, modulo the delivered QE of the CCD 
(assumed here to be 60%, but likely will be higher.) The resolution 
will be about 6 km/sec (current is 9 km/sec), but possibly as good as 
4 km/sec (the design value).

Projects with some objects at mag. 16, with a desire to go to 18 in 
long exposures, would be ideal.

The science now going in is
abundances in M giants
abundances in Cepheids (both G. Wallerstein)
distances to HVCs, using RR Lyr stars
characteristics of HVCs, using AGNs as background sources
diffuse interstellar bands in very reddened stars (all York)

Thanks, for any contributions.

-- 
Dr. Donald G. York
Horace B. Horton Professor of Astronomy and Astrophysics

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