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Dear colleagues,
Our paper on HP And was accepted for publication in IBVS (No. 5116),
reporting that the object which has been suggested to be HP And
is a late-type galaxy. The text file is attached below. The PDF
file is available at
http://vsnet.kusastro.kyoto-u.ac.jp/pub/vsnet/preprints/HP_And/hpand.pdf .
Best regards,
Daisaku Nogami
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\documentstyle[twoside,epsf]{article}
\input ibvs2.sty
\begin{document}
\IBVShead{5116}{xx July 2001}
\IBVStitletl{On the nature of the suspected dwarf nova, HP
Andromedae\footnote{Based on data collected at Subaru Telescope, which
is operated by the National Astronomical Observatory of Japan.}}{}
\IBVSauth{NOGAMI, D.$^{1}$, ISHIOKA, R.$^2$, MAKITA, M.$^2$, KATO,
T.$^2$, YAMAOKA, H.$^3$, UEMURA, M.$^2$, MINESHIGE, S.$^4$}
\IBVSinst{Hida Observatory, Kyoto University, Kamitakara, Gifu
506-1314, Japan, e-mail: nogami@kwasan.kyoto-u.ac.jp}
\IBVSinst{Dept. of Astronomy, Kyoto University, Kyoto 606-8502, Japan,
e-mail: (ishioka, uemura, tkato,
makoto)@kusastro.kyoto-u.ac.jp}
\IBVSinst{Faculty of Science, Kyushu University, Fukuoka 810-8560,
Japan, e-mail: yamaoka@rc.kyushu-u.ac.jp}
\IBVSinst{Yukawa Institute for Theoretical Physics, Kyoto University,
Kyoto 606-8502, Japan, e-mail: minesige@yukawa.kyoto-u.ac.jp}
\SIMBADobjAlias{HP And}{}
\IBVStyp{GAL}
\IBVSkey{dwarf nova}
\IBVSabs{The object having been identified with HP And is not a dwarf
nova.}
\begintext
Seliwanow (1926) reported on a discovery of a variable star designated
as 126.1925 at a photographic magnitude of 10.5 in one plate among four
searched, and showed a hand-drawn chart. Brun, Petit (1957) listed this
object as a suspected dwarf nova. The formal variable star name HP And
was given in the 62nd Name List (Kukarkin et al. 1976). The object has
been systematically monitored by a number of amateur astronomers
(e.g. VSOLJ, VSNET members) since the publication on this object in
General Catalogue of Variable Stars fourth edition (Kholopov et al
1985), but no secure outburst has been recorded.
The quiescent identification was searched by Kato (1990, unpublished)
by comparison with the POSS prints. A quiescent counterpart, selected
by its relatively bright appearance on POSS O plate, has been suggested,
and a CCD $V$-band chart marking on this object was distributed among
world-wide observers. An attempt of spectroscopic confirmation of the
dwarf nova nature by Zwitter, Munari (1994) failed due to its faintness
($V>17.0$) at their observation. Misselt (1996) and Skiff (1998) gave
secondary photometric standard stars around HP And. Downes et
al. (2001) identified an object on a Digitized Sky Survey plate with HP
And (http://icarus.stsci.edu/~downes/cvcat/). This variable star was
not found in the 2MASS Second Incremental Data Release (Hoard et
al. 2002).
The object has recently received special attention because the suggested
outburst amplitude may be comparable to those of WZ Sge stars
(e.g. Kato et al. 2001), if the object is indeed a dwarf nova.
To reveal the nature of this suspected dwarf nova HP And, we made
an observation at Subaru telescope during spare time assigned to the
proposal ID o02115. A non-filtered image was obtained with an exposure
time of 30 sec at 2002 October 10.495(UT) by the Faint Object Camera and
Spectrograph (FOCAS, see Kashikawa et al. 2002). The limiting
magnitude of the image is estimated to be 25.0, or larger.
Fig. 1 shows a chart around HP And extracted from the de-biased
Subaru/FOCAS image. The suspected object is definitely a late-type
galaxy with a relatively strong bulge condensation. The object certainly
looks non-stellar on a DSS II image (Fig 2), although it was not clear
on POSS I plates. For comparison, we put the scanned chart in Seliwanow
(1926) in Fig. 3. This galaxy is listed in the USNO-B1.0 catalog as ID
1314-0006148 with $B1=19.56, B2=18.78, R1=17.69, R2=16.99$, and is
identified in the APM-North Catalogue (McMahon et al. 2000) with
EO1243-0297148 which has a major axis diameter of 8.7 arcsec in $R$ band
and a ellipticity of 0.18.
\IBVSfig{10cm}{hpand_fig1.ps}{A Subaru/FOCAS image of HP And. The field of
view (FOV) is about $1'\times1'$. North is up, and East is left. The
seeing is 0.33$''$. The limiting magnitude is estimated to be 25.0 or
larger. The object having been identified with HP And clearly has
spiral arms, and is a galaxy, thus.}
\IBVSfig{10cm}{hpand_fig2.eps}{A chart taken from the Digitized Sky Survey 2nd
in I band (Plate ID: A25N). The suspected object at the center looks
non-stellar. The FOV is $5'\times5'$.}
If HP And is a variable star in our Galaxy, superposed on the anonymous
galaxy, the amplitude must exceed 10 mag and be a nova, or a dwarf nova
with a quite large amplitude. Since the galactic latitude is high
(-21$^\circ$), this should be one of rare cataclysmic variable stars in
halo. If HP And is a transient object in the anonymous galaxy, a
possibility of a supernova is not likely because the variable star at
the maximum was too luminous compared to the host galaxy. A GRB
afterglow similar to the nearby GRB 030329 might be caught by chance.
The other possibilities are spurious detection, such as a ghost of a
bright star, a plate defect, inaccuracy of the hand-drawn chart, and so
on. Close examination of the original plate and the astrometry will
yield a fruitful result.
\IBVSfig{10cm}{hpand_fig3.ps}{The scanned chart in Seliwanow (1926).}
\vskip 3mm
We deeply thank Y. Ohyama and the support staffs for their help during
the observation at Subaru telescope.
This research has made use of an image of the Digitized Sky Survey
(http://vsnet-gsss.stsci.edu/DSS/dss\_home.htm), the USNOFS Catalogue
Archive operated by the United States Naval Observatory, Flagstaff
Station\\ (http://vsnet.nofs.navy.mil/data/fchpix/). This work is partly
supported by a Research Fellowship of the Japan Society for the
Promotion of Science for Young Scientists (MU), and by a grant-in-aid
[13640239, 15037205 (TK), 14740131 (HY)] from the Japanese Ministry of
Education, Culture, Sports, Science and Technology.
\references
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Downes, R.A., Webbink, R.F., Shara, M.M., Ritter, H., Kolb, U.,
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Hoard, D.W., Wachter, S., Clark, L.L., Bowers, T.P., 2002, {\it ApJ},
{\bf 565}, 511
Kashikawa, N., Aoki, K., Asai, R., Ebizuka, N., Inata, M., Iye, M.,
Kawabata, K.S., Kosugi, G., et al., 2002, {\it PASJ}, {\bf 54}, 819
Kato, T., Sekine, Y., Hirata, R., 2001, {\it PASJ}, {\bf 53}, 1191
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Gorynya, N.A., Kireeva, N.N., Kukarkina, N.P., Kurochkin, N.E.,
Medvedeva, G.I., Perova, N.B., Shugarov, S.Yu., 1985,
General Catalogue of Variable Stars, 4th edition (Moscow,
Nauka Publishing House)
Kukarkin, B.V., Kholopov, P.N., Fedorovich, V.P., Kireyeva, N.M.,
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Mayall, M.W., 1968, {\it Journal of the Royal Astronomical Society of
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McMahon, R.G., Irwin, M.J., Maddox, S.J., 2000, The APM-North Catalogue
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\end{document}
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vsnet-adm@kusastro.kyoto-u.ac.jp
