1. Overview
2. Targets and Strategy
3. Short summary of scientific backgrounds
We have got 17-hour ToO (Target of Opportunity) time of
Cerro Tololo 1.5-m telescope during August 1 - December 23, 2005.
This ToO is aimed at prompt spectroscopy during outbursts of
intermediate polars (IPs). We'd like to call for observations
of our targets in order to monitor the targets and promptly trigger
the ToOs. If you have an interest to our project, please let me
know (uemuram(at)hiroshima-u.ac.jp).
We are planning another ToOs for northern IPs and fainter IPs
with other telescopes in future. This is the first step for
the project.
All IPs can be our targets when they start very rare and
unprecedented outbursts.
The list below is our recommended targets, which have
experienced IP or IP-like outbursts before.
We'd like to ask collaborators to monitor these objects
as frequently as possible, and when an outburst occurs, to
report us promptly.
Class 1 (high priority):
TV Col: dq, 05:29:25.44, -32:49:04.5, 13.6V - 14.1V
Short outbursts with a low amplitude.
Class 2 (middle priority):
CW Mon: ug, 06:36:54.53, +00:02:16.3, 11.9v - 16.3v
Atypically rapid decline from outbursts. IP?
RX J0944.5+0357: dq, 09:44:31.72, +03:58:05.4, 12.8-16.3B
Rapid decline from dwarf nova outbursts.
NSV10934: ugsu, 18:40:52.61, -83:43:08.6, 11.2p - <15.0p
Atypically rapid decline from normal outbursts. IP?
Only normal outbursts will be a target for the ToO.
GZ Cnc: ug/dq:, 09:15:51.70, +09:00:50.2, 13.1p - 15.4p
Clustering of outbursts. IP?
AH Eri: ug/dq:, 04:22:38.10, -13:21:30.2, 13.5V - 18.5V
IP candidate showing dwarf nova outbursts.
Followings are IPs or IP candidates whose outbursts have not been
reported. They can be ToO targets if unprecedented outbursts are
found. Their information of positions and magnitudes are from
Catalog by Downes et al.
Several IPs show outbursts, like dwarf novae. It has been,
however, suspected that their mechanism may be different from
that of dwarf novae. This is because some of IP outbursts show
peculiar characteristics compared with dwarf novae.
TV Col, for example, show very short outburst with a low amplitude.
Hellier & Buckley (1993) suggested that outbursts of TV Col are
not caused by the disk instability (a good model for dwarf novae),
but caused by the mass-transfer instability.
On the other hand, recent observations have revealed that
there are more various types in IP outbursts. IP outbursts are
not always "low amplitude" and "very short", like TV Col.
HT Cam and DO Dra, for example, show very short outbursts with
high amplitudes. While the IP outburst nature is not established,
several dwarf novae are known to show outbursts like IP's.
CW Mon and RX J0944.5+0357, for example, show atypically rapid
declines from outbursts, which are remniscent of IP outbursts.
The final goal of our project is to understand outbursts
of IPs and IP candidates; whether their mechanisms are same or not;
if they are same, what causes the observed diversity of them.
Due to their rapid time evolution, spectroscopic observations have
poorly been reported during outbursts. For the first step of
this project, we now propose prompt spectroscopy during outbursts
of southern bright IPs with the CTIO 1.5-m telescope.
Class 3 (low priority):
SDSS J233325.92+152222.2: cv, 23:33:25.92, +15:22:22.2, g=18.75
SDSS IP candidate. No outburst behavior is reported.
If its unprecedented, bright outburst (~13-14 mag) is
discovered, the object can be a target of the ToO.
UU Col: dq, 05:12:13.22, -32:41:39.8, 17.3B - 18.2B
soft IP. No outburst behavior is reported.
If its unprecedented, bright outburst (~13-14 mag) is
discovered, the object can be a target of the ToO.
V436 Car: dq, 07:44:57.99, -52:57:11.7, 13.6 B - 15.8 B
No outburst behavior is reported, while Would & Warner
(2002) reported its spectrum similar to that of dwarf novae
in quiescence. The object is a long variable with an
amplitude of ~2 mag.
If it experienced a sudden brightening to 11-12 mag,
the object can be a target of the ToO.
BW Scl: ugwz/dq, 23:53:00.82, -38:51:46.0, 16.5V
Low mass-transfer system (possible IP?) (Abbott et al. 1997).
If its unprecedented, bright outburst (~13-14 mag) is
discovered, the object can be a target of the ToO.
Class 4 (other IPs or IP candidates: bright sources):
KUV 03580+0614: 04:00:37.25, +06:22:46.2, 14.6V - 15.5V
TX Col: 05:43:20.23, -41:01:54.6, 14.5B - 15.8B
V347 Pup: 06:10:33.66, -48:44:25.4, 13.4V - 15.8V
AH Men: 06:11:44.46, -81:49:23.1, 13.2V - 14.0V
BG CMi: 07:31:29.00, +09:56:23.1, 14.3V - 15.4V
PQ Gem: 07:51:17.33, +14:44:23.9, 14.1V - 14.5V
AE Aqr: 20:40:09.16, -00:52:15.1, 9.8V - 11.8V
FO Aqr: 22:17:55.39, -08:21:03.8, 13.0v - 14.0v
AO Psc: 22:55:17.99, -03:10:40.0, 13.3V - 15.0V
Class 5 (other IPs or IP candidates: faint sources):
NGC 104: 00:24:04.29, -72:04:57.8, 19.8V
1RXS J025538-224655: 02:55:38.03, -22:47:02.7, 18.0v
UU Col: 05:12:13.22, -32:41:39.8, 17.3B - 18.2B
V348 Pup: 07:12:32.90, -36:05:38.6, 15.5V - 17.0V
GI Mon: 07:26:47.10, -06:40:29.5, 5.6p - 16.6B, (na)
WX Pyx: 08:33:05.69, -22:48:31.8, 16.2V - 17.7V
2236+0052: 22:38:43.83, +01:08:20.7, 18.5j
XY Ari: 02:56:08.1, +19:26:34., 13.5j - 17.6j
Our project requires to start ToOs as early as possible in outbursts.
When an alert of one of the above targets is reported to us, we will
decide whether ToOs are triggered or not, based on observations
last few days. If there is no observation in the last few days,
we will not trigger ToO because we cannot confirm whether we can
observe an early phase of the outburst.
Our ToO tims is 17 hours, that is, 2 nights.
We will carefully select the best opportunity for our goal.
3. Short summary of scientific backgrounds
Makoto Uemura
Hiroshima University, Japan
uemuram@hiroshima-u.ac.jp
Co-Investigators: R. Mennickent, S. Mineshige, T. Kato,
D. Nogami, R. Ishioka, and A. Imada