Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NICMOS imaging search for damped Lya galaxies   We are engaged in a programme of imaging with the STIS and NICMOS (NIC2)
instruments aboard the Hubble Space Telescope (HST), to search for the galaxy
counterparts of 18 high-redshift z>1.75 damped Lya absorption lines and 5
Lyman-limit systems seen in the spectra of 16 target quasars. This paper
presents the results of the imaging campaign with the NIC2 camera. We describe
the steps followed in reducing the data and combining in mosaics, and the
methods used for subtracting the image of the quasar in each field, and for
constructing error frames that include the systematic errors associated with
the psf subtraction. To identify candidate counterparts, that are either
compact or diffuse, we convolved the image and variance frames with circular
top-hat filters of diameter 0.45 and 0.90 arcsec respectively, to create frames
of summed S/N within the aperture. For each target quasar we provide catalogues
listing positions and aperture magnitudes of all sources within a square of
side 7.5 arcsec centred on the quasar, detected at S/N>6. We find a total of 41
candidates of which three have already been confirmed spectroscopically as the
counterparts. We provide the aperture magnitude detection limits as a function
of impact parameter, for both detection filters, for each field. The average
detection limit for compact (diffuse) sources is H(AB)=25.0 (24.4) at an
angular separation of 0.56 arcsec (0.79 arcsec) from the quasar, improving to
H(AB)=25.5 (24.8) at large angular separations. For the brighter sources we
have measured the half-light radius and the n parameter of the best-fit
deconvolved Sersic-law surface-brightness profile, and the ellipticity and
orientation.

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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio