A New Mid-Infrared Camera for Ground-Based Astronomy and an Infrared
Study of Planetary Nebulae
Joseph Lee Hora
This version of the above titled dissertation is available on-line below.
You are allowed to obtain one electronic copy and one "hard" or printed copy
of the dissertation. This work is not in the public domain. All rights
reserved. No part of the contents of this dissertation may be reproduced or
transmitted in any form or by any means without the written permission of
the copyright holder (Joseph Hora).
Original copyright notice
This dissertation has been submitted in partial fulfillment of requirements for an
advanced degree at The University of Arizona and is deposited in the University Library
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This dissertation is composed of two parts. The first part is a description of the
Mid-Infrared Array Camera (MIRAC), a new camera for ground-based astronomy. The
second part of this dissertation is an infrared study of planetary nebulae utilizing
observations with the new camera.
MIRAC is a collaborative effort among the University of Arizona, Smithsonian
Astrophysical Observatory, and Naval Research Laboratory. It currently utilizes a
Hughes 20x64 Si:As IBC detector array, which is sensitive to infrared (IR) radiation from
2 to 26 microns. The camera is equipped with 10% bandwidth filters at 2.2, 3.8, 4.6, 8.8, 9.8,
11.7, and 12.5 microns, and a wide band 8.0 to 12.8 micron "N" filter. There is also a 20% filter
at 20.5 microns, and a 8-14 micron CVF with a resolution of 1.8%. The MIRAC electronics
provides timing signals and coadds successive frames at a maximum rate of 10 KHz for
the full array, and higher rates for a partial array readout. The data are transferred via
a serial interface to a PC for storage and further processing. The camera recently
achieved a NEFD of .010 Jy/arcsec2 at 8.8, 11.7, and 12.5 microns for a 900 second on-source
integration on the Steward Observatory 1.5 m telescope.
Planetary Nebulae (PN) are formed when a star is in the post-Asymptotic Giant
Branch stage of evolution. The ejection of circumstellar material is an important
enrichment mechanism for the interstellar medium. In many PN, there is an excess of
emission in the IR, indicating the presence of dust. There are several different
components seen in the IR emission, including a family of unidentified IR (UIR) emission
features at 3.3, 6.2, 7.7, and 11.3 microns. Images in the near- and mid-IR are presented here
for the following PN: IC 418, BD+30°3639, J 900, NGC 2392, NGC 6543, AFGL 2688, and
M 2-9. In IC 418 and BD+30°3639, the SiC and UIR emission is seen to be spatially
distinct from the IR continuum. In NGC 2392 and NGC 6543, evidence for excess
emission is seen in the distribution of the near-IR flux. In the bipolar nebulae AFGL
2688 and M 2-9, structures in the IR emission are seen that could be related to the
equatorial density enhancements that have caused the bipolar morphology.
Downloading the files
The dissertation is available as a single PDF format file, and has also
been divided up into seven parts to make downloading
If you have difficulty getting these, contact me (see below). Also, a copy of
the dissertation can be obtained from University Microfilms, Inc. (UMI) -- see
the contact information below. The UMI document number of this work is 9210322.
There may be some discrepancies between the original published dissertation and
this on-line version. The figures are on the same page as in the original, but
some of the text may be slightly different due to the conversion in WordPerfect
5.0 from a HP printer to Postscript. If referring to page numbers when quoting
from the work, please refer to the page numbers in the original manuscript.
Adobe PDF format
PDF versions of the following files are available, as well as the total
dissertation as one file. Warning- it is 13MB in size! PDF viewers are
available free for most platforms (the Acrobat reader) -- see the
Adobe home page for more
Full Dissertation - PDF format
Full Dissertation (pdf format). (Size: 13.2MB)
Dissertation Parts - PDF format
- Part 1 - MIRAC - A Mid-Infrared Camera for Astronomy
- Part 2 - An Infrared Study of Planetary Nebulae
- Appendicies, References
Contact info: Joseph Hora
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, MS-65
Cambridge, MA 02138-1516
Contact info: University Microfilms, Inc.
300 North Zeeb Rd.
Ann Arbor, MICHIGAN 48106-1346
(313)761-4700 or (800)521-0600
Web Address: http://www.umi.com
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Last modified 1999 August 12