%...Journal: PASP %...MainTag: '1.0 mag) object. We suggest that this fainter object could be the survivor of SN 1961V. Forthcoming {\em HST} observations may settle this issue. %K Galaxies: Individual: NGC Number: NGC 1058 %K Galaxies: Stellar Content %K Stars: Evolution %K Stars: Variables: Other %K Stars: Supernovae: General %K Stars: Supernovae: Individual: Alphanumeric: SN 1961V %I (1) Based on observations made with the NASA/ESA {\em Hubble Space Telescope}, obtained from the data archive of the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. %R 2002PASP..114..708H %F ori/PASPv114n797 %J-720 %T The {\em Y} Band at 1.035 Microns: Photometric Calibration and the DwarfStellar/Substellar Color Sequence. %A Hillenbrand, Lynne A. %A Foster, Jonathan B. %I California Institute of Technology, Department of Astronomy, MS 105-24, Pasadena, CA 91125; (lah@astro.caltech.edu) %A Persson, S.E. %I Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 %A Matthews, K. %I California Institute of Technology, Palomar Observatory, MS 320-47, Pasadena, CA 91125 %B We define and characterize a photometric bandpass (called ``{\em Y}'') that is centered near 1.035 {mu}m, in between the traditionally classified ``optical'' and ``infrared'' spectral regimes. We present {\em Y} magnitudes and {\em Y-H} and {\em Y-K} colors for a sample consisting mostly of photometric and spectral standards, spanning the spectral type range sdO to T5 V. Deep molecular absorption features in the near-infrared spectra of extremely cool objects are such that the {\em Y-H} and {\em Y-K} colors grow rapidly with advancing spectral type especially from late M through mid-L, substantially more rapidly than {\em J-H} or {\em H-K}, which span a smaller total dynamic range. Consistent with other near-infrared colors, however, {\em Y-H} and {\em Y-K} colors turn blueward in the L6-L8 temperature range, with later T-type objects having colors similar to those of warmer M and L stars. {\em Y-J} colors remain constant at 1.0+/-0.15 mag from early-L through late-T dwarfs. The slope of the interstellar reddening vector within this filter is A_Y_=0.38A_V_. Reddening moves stars nearly along the {\em YHK} dwarf color sequence, making it more difficult to distinguish unambiguously very low mass candidate brown dwarf objects from higher mass stars seen, e.g., through the Galactic plane or toward star-forming regions. Other diagrams involving the {\em Y} band may be somewhat more discriminating. %K ISM: Dust, Extinction %K infrared: stars %K Instrumentation: Photometers %K Stars: General %K Stars: Low-Mass, Brown Dwarfs %R 2002PASP..114..721P %F ori/PASPv114n797 %J-747 %T The 2001 Superoutburst of WZ Sagittae. %A Patterson, Joseph (1) %A Masi, Gianluca (2) %A Richmond, Michael W.(3) %A Martin, Brian (4) %A Beshore, Edward (5) %A Skillman, David R.(6) %A Kemp, Jonathan (1)(7)(8) %A Vanmunster, Tonny (9) %A Rea, Robert (10) %A Allen, William (11) %A Davis, Stacey (3) %A Davis, Tracy (3) %A Henden, Arne A.(12) %A Starkey, Donn (13) %A Foote, Jerry (14) %A Oksanen, Arto (15) %A Cook, Lewis M.(16) %A Fried, Robert E.(17) %A Husar, Dieter (18) %A Nov\'ak, Rudolf (19) %A Campbell, Tut (20) %A Robertson, Jeff (20) %A Krajci, Thomas (21) %A Pavlenko, Elena (22) %A Mirabal, Nestor (1) %A Niarchos, Panos G.(23) %A Brettman, Orville (24) %A Walker, Stan (25) %B We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at V=15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ~1 mag amplitude and 2 day recurrence time; these ``echo outbursts'' are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 days, the star began a slow decline to quiescence.\par Periodic waves in the light curve closely followed the pattern seen in the 1978 superoutburst: a strong orbital signal dominated the first 12 days, followed by a powerful {\em common superhump} at 0.05721(5) day, 0.92(8)% longer than P_orb_. The latter endured for at least 90 days, although probably mutating into a ``late'' superhump with a slightly longer mean period [0.05736(5) day]. The superhump appeared to follow familiar rules for such phenomena in dwarf novae, with components given by linear combinations of two basic frequencies: the orbital frequency {omega}_o_ and an unseen low frequency {Omega}, believed to represent the accretion disk's apsidal precession. Long time series reveal an intricate fine structure, with ~20 incommensurate frequencies. Essentially all components occurred at a frequency n{omega}_o_-m{Omega}, with m=1, {hellip}, n. But during its first week, the common superhump showed primary components at n{omega}_o_-{Omega}, for n=1, 2, 3, 4, 5, 6, 7, 8, 9 (i.e., m=1 consistently); a month later, the dominant power shifted to components with m=n-1. This may arise from a shift in the disk's spiral-arm pattern, likely to be the underlying cause of superhumps.\par The great majority of frequency components are redshifted from the harmonics of {omega}_o_, consistent with the hypothesis of apsidal advance (prograde precession). But a component at 35.42 cycles day^-1^ suggests the possibility of a retrograde precession at a different rate, probably N=0.13+/-0.02 cycles day^-1^.\par The eclipses permit measuring the location and brightness of the mass-transfer hot spot. The disk must be very eccentric and nearly as large as the white dwarf's Roche lobe. The hot-spot luminosity exceeds its quiescent value by a factor of up to 60. This indicates that enhanced mass transfer from the secondary plays a major role in the eruption. %K accretion, accretion disks %K Stars: Binaries: Close %K Stars: Novae, Cataclysmic Variables %K Stars: Individual: Constellation Name: WZ Sagittae %I (1) Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027; (jop@astro.columbia.edu), (abulafia@astro.columbia.edu). %I (2) Center for Backyard Astrophysics (Italy), Via Madonna de Loco, 47, 03023 Ceccano FR, Italy; (gianmasi@fr.flashnet.it). %I (3) Rochester Institute of Technology, Department of Physics, 85 Lomb Memorial Drive, Rochester, NY 14623; (mwrsps@rit.edu), (smd5659@osfmail.rit.edu), (tadsps@rit.edu). %I (4) King's University College, Department of Physics, 9125 50th Street, Edmonton, AB T5H 2M1, Canada; (bmartin@kingsu.ab.ca). %I (5) Center for Backyard Astrophysics (Colorado), 14795 East Coachman Drive, Colorado Springs, CO 80908; (ebeshore@pointsource.com). %I (6) Center for Backyard Astrophysics (East), 9517 Washington Avenue, Laurel, MD 20723; (dskillman@home.com). %I (7) Joint Astronomy Centre, University Park, 660 North A`oh{omacr}k{umacr} Place, Hilo, HI 96720; (j.kemp@jach.hawaii.edu). %I (8) Visiting Astronomer, Cerro Tololo Interamerican Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation. %I (9) Center for Backyard Astrophysics (Belgium), Walhostraat 1A, B-3401 Landen, Belgium; (tonny.vanmunster@advalvas.be). %I (10) Center for Backyard Astrophysics (Nelson), 8 Regent Lane, Richmond, Nelson, New Zealand; (reamarsh@ihug.co.nz). %I (11) Center for Backyard Astrophysics (Blenheim), 83 Vintage Lane, RD 3, Blenheim, New Zealand; (wallen@voyager.co.nz). %I (12) United States Naval Observatory, Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002; (aah@nofs.navy.mil). %I (13) Center for Backyard Astrophysics (Indiana), 2507 County Road 60, Auburn, IN 46706; (starkey@fwi.com). %I (14) Center for Backyard Astrophysics (Utah), 4175 East Red Cliffs Drive, Kanab, UT 84741; (jfoote@scopecraft.com). %I (15) Center for Backyard Astrophysics (Finland), Vertaalantie 449, Nyr\"ol\"a, Finland; (arto.oksanen@jklsirius.fi). %I (16) Center for Backyard Astrophysics (Concord), 1730 Helix Court, Concord, CA 94518; (lcoo@yahoo.com). %I (17) Center for Backyard Astrophysics (Flagstaff), Braeside Observatory, P.O. Box 906, Flagstaff, AZ 86002; (captain@asu.edu). %I (18) Center for Backyard Astrophysics (Hamburg), Himmelsmoor 18, D-22397 Hamburg-Duvenstedt, Germany; (husar_d@compuserve.com). %I (19) Nicholas Copernicus Observatory, Kravi Hora 2, Brno 616 00, Czech Republic; (novak@hvezdarna.cz). %I (20) Arkansas Tech University, Department of Physical Science, 1701 North Boulder Avenue, Russellville, AR 72801; (jeff.robertson@atu.edu), (tutsky@yahoo.com). %I (21) Center for Backyard Astrophysics (New Mexico), 1688 Cross Bow Circle, Clovis, NM 88101; (krajcit@3lefties.com). %I (22) Crimean Astrophysical Observatory, P/O Nauchny, 334413 Crimea, Ukraine; (pavlenko@crao.crimea.ua). %I (23) University of Athens, Department of Astrophysics, Astronomy, Mechanics, Panepistimipolis, GR-157 84, Zografos, Athens, Greece; (pniarcho@cc.uoa.gr). %I (24) Center for Backyard Astrophysics (Huntley), 13915 Hemmingsen Road, Huntley, IL 60142; (rivendell.astro@worldnet.att.net). %I (25) Center for Backyard Astrophysics (Waiharara), Wharemaru Observatory, Post Office Box 13, Awanui 0552, New Zealand; (astroman@voyager.co.nz). %R 2002PASP..114..748H %F ori/PASPv114n797 %J-755 %T Measuring the Boundary Layer and Inner Accretion Disk Temperatures for WX Ceti during Superoutburst(1). %A Howell, Steve B. %I Astrophysics Group, Planetary Science Institute, Tucson, AZ 85705; (howell@psi.edu) %A Fried, Robert %I Braeside Observatory, P.O. Box 906, Flagstaff, AZ 86002; (captain@asu.edu) %A Szkody, Paula %I Department of Astronomy, University of Washington, Seattle, WA 98195; (szkody@alicar.astro.washington.edu) %A Sirk, Martin M. %I Space Sciences Laboratory, University of California, Berkeley, CA 94720; (sirk@ssl.berkeley.edu) %A Schmidt, Gary %I Department of Astronomy, University of Arizona, Tucson, AZ 85706; (gschmidt@as.arizona.edu) %B We obtained EUV photometry, optical spectroscopy, and multicolor optical photometry for WX Cet during its 1998 November superoutburst. WX Cet is only the second short-period, low mass transfer cataclysmic variable (TOAD) to ever be observed in the EUV. Our determined superhump period is consistent with that found by Kato et al. (0.059 day), and we confirm that superhumps are gray in the optical. The optical spectra provide direct evidence that the line emission region is optically thick, and our multiwavelength photometric measurements are used to determine the inner accretion disk and boundary layer temperatures during superoutburst. Using a determined distance to WX Cet of ~130 pc, we find T_ID_=21,000 K and T_BL_~72,500 K. Both values are in good agreement with that expected by models of the superoutburst continuum being produced by the inner disk and boundary layer. %K accretion, accretion disks %K Stars: Novae, Cataclysmic Variables %K stars: individual (WX Ceti) %I (1) Some observations were made with the Apache Point Observatory (APO) 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium (ARC). %R 2002PASP..114..756H %F ori/PASPv114n797 %J-760 %T The Classification and Orbital Period of WD 2154+408: A New Short-Period Post-Common-Envelope Binary. %A Hillwig, Todd C.(1)(2) %A Gale, Ashley A.(1) %A Honeycutt, R.Kent (1) %A Rengstorf, Adam W.(1) %B We present orbit-sampled photometry of the binary system WD 2154+408. The photometric study reveals a period of P=0.26772 day, which is taken to be the orbital period of the binary. No evidence is seen for either an accretion disk or mass transfer, leading to the conclusion that WD 2154+408 is not a contact or semidetached system but has detached components with a visible irradiation effect. The short orbital period also leads to the conclusion that the system passed through a common-envelope phase at some time in the past. A single spectrum is shown exhibiting both narrow emission and broad absorption components of the H{beta} line. This and the photometric variations are consistent with the system being a post-common-envelope binary consisting of a hot white dwarf primary and a cool irradiated companion. %K Stars: Binaries: Close %K stars: individual (WD 2154+408) %I (1) Department of Astronomy, Indiana University, Bloomington, IN 47405; (honey@astro.indiana.edu), (arengsto@astro.indiana.edu). %I (2) Current address: Center for High Angular Resolution Astronomy, Georgia State University, Atlanta, GA 30303; (thillwig@chara.gsu.edu). %R 2002PASP..114..761H %F ori/PASPv114n797 %J-765 %T Faint Star Counts in the Near-Infrared. %A Hutchings, J.B. %A Stetson, P.B. %I Herzberg Insitute of Astrophysics, National Research Council of Canada, Victoria, BC V9E 2E7, Canada; (john.hutchings@nrc.ca) %A Robin, A. %I Observatiore de Besan\c{c}on, BP 1615, F-25010 Besan\c{c}on Cedex, France; (annie@obs-besancon.fr) %A Webb, T. %I Department of Astronomy, University of Toronto, Toronto, ON M5S 1A1, Canada; (webb@astro.utoronto.ca) %B We discuss near-infrared star counts at the Galactic pole with a view to guiding the {\em Next Generation Space Telescope} and ground-based near-infrared cameras. Star counts from deep {\em K}-band images from the Canada-France-Hawaii Telescope are presented and compared with results from the 2MASS survey and some galaxy models. With appropriate corrections for detector artifacts and galaxies, the data agree with the models down to K~18 but indicate a larger population of fainter red stars. There is also a significant population of compact galaxies that extend to the observational faint limit of K=20.5. Recent galaxy models agree well down to K~19 but diverge at fainter magnitudes. %K Galaxies: Evolution %K Galaxy: Halo %K infrared: galaxies %K instrumentation: high angular resolution %R 2002PASP..114..766Q %F ori/PASPv114n797 %J-769 %T Is the Algol-type Eclipsing Binary RX Geminorum a True Triple System. %A Qian, Shengbang (1)(2) %A Liu, Dengliang (3) %A Tan, Wenli (4) %A Soonthornthum, Boonrucksar (5) %B An analysis of the times of minimum light for the long-period Algol-type eclipsing binary RX Gem is presented based on a new linear ephemeris. The O-C curve shows a cyclic oscillation with a period of 55.7 yr and a semiamplitude of 0.0645 day. Assuming the change to be due to the presence of a ``third body'' revolving around the RX Gem system, the parameters of the third body's orbit are derived. Since the third-body assumption is in good agreement with the spectroscopic data from several authors and with published photometric solutions (Gaposchkin, Hall, & Walter; Giuricin et al.), RX Gem is likely to be a triple system. In this case, the third body is an A-type star in a circular orbit, which is nearly coplanar to the orbit of the eclipsing pair. However, the recent light-curve analysis by Olson & Etzel does not show any third light, so the third star (M_3_>2.41 M_{sun}_) may be an unseen neutron star or black hole. Additional eclipse timings over the next decade will be important to verify the presence of the third body. %K Stars: Binaries: Close %K stars: individual (RX Geminorum) %I (1) Yunnan Observatory, National Astronomical Observatories, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming, People's Republic of China; (qsb@netease.com). %I (2) United Laboratory of Optical Astronomy, Chinese Academy of Sciences (ULOAC). %I (3) The Second Middle School of Nayong County, Nayong 553300, Guizhou Province, People's Republic of China. %I (4) Department of Physics, Guizhou Normal University, Guiyang 550001, Guizhou Province, People's Republic of China. %I (5) Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. %R 2002PASP..114..770L %F ori/PASPv114n797 %J-779 %T On the Accuracy of the Signal-to-Noise Estimates Obtained with the Exposure-Time Calculator of the Wide Field Planetary Camera 2 on Board the {\em Hubble Space Telescope}. %A Li Causi, Gianluca %I Osservatorio Astronomico di Roma, Via Frascati 33, 00040, Monteporzio Catone (RM), Italy; (licausi@coma.mporzio.astro.it) %A De Marchi, Guido (1) %I European Space Agency, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218; (demarchi@stsci.edu) %A Paresce, Francesco %I European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei M\"unchen, Germany; (fparesce@eso.org) %B We have studied the accuracy and reliability of the exposure-time calculator (ETC) of the Wide Field Planetary Camera 2 (WFPC2) on board the {\em Hubble Space Telescope} ({\em HST}) with the objective of determining how well it represents actual observations and therefore how much confidence can be invested in it and in similar software tools. We have found, for example, that the ETC gives, in certain circumstances, very optimistic values for the signal-to-noise ratio (S/N) of point sources. These values overestimate by up to a factor of 2 the {\em HST} performance when simulations are needed to plan deep-imaging observations, thus bearing serious implications on observing-time allocation. For this particular case, we calculate the corrective factors to compute the appropriate S/N and detection limits, and we show how these corrections vary with field crowding and sky background. We also compare the ETC of the WFPC2 with a more general ETC tool, which takes into account the real effects of pixel size and charge diffusion. Our analysis indicates that similar problems may afflict other ETCs in general, showing the limits to which they are bound and the caution with which their results must be taken. %K Instrumentation: Detectors %K space vehicles: instruments %K Stars: Imaging %I (1) Affiliated with the Research and Science Support Department of ESA. %R 2002PASP..114..780B %F ori/PASPv114n797 %J-794 %T A Large-Area CCD Camera for the Schmidt Telescope at the Venezuelan National Astronomical Observatory. %A Baltay, C.(1) %A Snyder, J.A.(1)(2) %A Andrews, P. %A Emmet, W. %A Schaefer, B.(3) %A Sinnott, J.(4) %I Department of Physics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121; (charles.baltay@yale.edu), (jeffrey.snyder@yale.edu), (peter.andrews@yale.edu), (william.emmet@yale.edu) %A Bailyn, C. %A Coppi, P.(5) %A Oemler, A.(6) %A Sabbey, C.N.(7) %A Sofia, S. %A van Altena, W. %A Vivas, A.K. %I Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101; (bailyn@astro.yale.edu), (coppi@astro.yale.edu), (sofia@astro.yale.edu), (vanalten@astro.yale.edu), (vivas@astro.yale.edu) %A Abad, C. %A Bongiovanni, A. %A Brice\~no, C. %A Bruzual, G. %A Della Prugna, F. %A Magris, G. %A S\'anchez, Ge. %A S\'anchez, Gu. %A Schenner, H. %A Stock, J. %I Centro de Investigaciones de Astronom\'ia, Apartado Postal 264, M\'erida 5101-A, Venezuela; (abad@cida.ve), (abongiov@cida.ve), (briceno@cida.ve), (bruzual@cida.ve), (dellap@cida.ve), (magris@cida.ve), (gerardo@cida.ve), (sanchez@cida.ve), (hans@cida.ve), (stock@cida.ve) %A Adams, B. %A Gebhard, M. %A Honeycutt, R.K. %A Musser, J. %A Rengstorff, A. %I Department of Astronomy, Indiana University, Swain Hall West 319, 727 East 3d Street, Bloomington, IN 47405-7105; (adams@astro.indiana.edu), (gebhard@astro.indiana.edu), (honey@astro.indiana.edu), (musser@astro.indiana.edu), (arengsto@astro.indiana.edu) %A Ferrin, I. %A Fuenmayor, F. %A Hernandez, J. %A Naranjo, O. %A Rosenzweig, P. %I Universidad de Los Andes, Apartado Postal 26, M\'erida 5251, Venezuela; (ferrin@ciens.ula.ve), (franfuen@ciens.ula.ve), (hernandj@ciens.ula.ve), (naranjo@ciens.ula.ve), (patricia@ciens.ula.ve) %A Harris, F.(8) %I Universities Space Research Association, US Naval Observatory, P.O. Box 1149, Flagstaff, AZ 86002-1149; (fhh@nofs.navy.mil) %A Geary, J. %I Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138; (jgeary@cfa.harvard.edu) %B We have designed, constructed, and put into operation a large-area CCD camera that covers a large fraction of the image plane of the 1 m Schmidt telescope at Llano del Hato in Venezuela. The camera consists of 16 CCD devices arranged in a 4x4 mosaic covering 2{deg}.3x3{deg}.5 of sky. The CCDs are 2048x2048 LORAL devices with 15 {mu}m pixels. The camera is optimized for drift-scan photometry and objective-prism spectroscopy. The design considerations, construction features, and performance parameters are described in the following paper. %K Cosmology: Observations %K Instrumentation: Detectors %K Surveys %I (1) Also Department of Astronomy, Yale University, New Haven, CT 06520-8101. %I (2) Corresponding author. %I (3) Current address: Department of Astronomy, University of Texas at Austin, RLM 15.308, C-1400, Austin, TX 78712-1083; (schaefer@astro.as.utexas.edu). %I (4) Current address: Cornell University, Ithaca, NY 14853-1501; (jps39@cornell.edu). %I (5) Also Department of Physics, Yale University, New Haven, CT 06520-8121. %I (6) Also Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101-1292; (oemler@ociw.edu). %I (7) Current address: Bogle Investment Management, Wellesley, MA 02481; (cns@boglefunds.com). %I (8) Current address: US Naval Observatory, Flagstaff, AZ 86002-1149. %R 2002PASP..114..795M %F ori/PASPv114n797 %J-796 %T Physical Properties of Giant Molecular Clouds in Nearby Starburst Galaxies. (Dissertation Summary). %A Meier, David S. %I Current address: Department of Astronomy, University of Illinois, Urbana-Champaign, 1002 West Green Street, Urbana, IL, 61801; (meierd@astro.uiuc.edu)Thesis work conducted at University of California, Los Angeles Ph.D. thesis directed by Jean L. Turner; Ph.D. degree awarded February 2002 %K Galaxies: Individual: Alphanumeric: IC 342 %K Galaxies: Individual: Name: Maffei 2 %K Galaxies: Individual: NGC Number: NGC 4826 %K Galaxies: Individual: NGC Number: NGC 6946 %K Galaxies: ISM %K Galaxies: Nuclei %K Galaxies: Starburst %K ISM: Molecules %K radio lines: galaxies