From jop at astro.columbia.edu Fri Jul 1 06:35:38 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 1 Jul 2005 06:35:38 -0400 (EDT) Subject: (cba:news) Old and new targets Message-ID: Dear CBAers, The star of the month, Var Nor 05 = ASAS1600-48, seems like it's about to dive off our radar screens. I've analyzed the data coming in and found that it really does deliver on its advance notices - the outburst really did seem like a WZ Sge-type, with a superhump sideband structure strongly insinuating an orbital period 1.0% less then P(superhump). This was a great thrill. These stars of very small Psh-Porb are likely to be the oldest of CVs, and the size of that period excess is usually the best indicator of its age (because it signifies the mass of the secondary). It would be nice to continue that campaign further... and it might be possible, since the star is now engaging in echo outbursts. If you can keep tracking and are willing to struggle with the field and the faintness, please do! But from this latitude I really don't have much idea what the star is doing... so you need to leaven (or replace) my advice with common sense! Here are the other southern targets du jour: 1. V1494 Aql. OK, it's +5 deg dec, but still.... We will conclude our 4-year study of this classical nova (1999) this year. No observations this year, but when last seen it was bright enough for CBA work. Nice 3-hour period, origin not yet securely known. 2. Other well-placed southern old novae. Berto tracks the recent ones pretty faithfully... and there are a whole bunch. Berto, which do you think is a good candidate for us? 3. RX1730-05 (Oph). Actually this is first priority (for sure), but Jennie tells me it has gone faint. If you can do it, this is the guy! There's a quite fast period it would be nice to track; but even if your exposure times knock it out, there's also the orbital period to find. A candidate at 16 hours - difficult for most observers, but red meat for the CBA - especially with Paul Warhurst still in Argentina. 4. V442 Oph. Pretty inviting target for CBA weaponry. We've not managed a really good campaign since 1995, and it would be lovely to have one. Very well placed in the sky! And in the NORTH: 1. RX1730-05 (Oph), subject to the above brightness worries. 2. V1494 Aql, a star for all latitudes. 3. IX Dra and MN Dra. These are two dwarf novae with very small superhump period excesses (Psh-Porb) reported. The data seemed kinda uncertain in both cases, but this is an important question to be really sure of! In fact, both of these are overall mystery stars with nearly everything up in the air - the recurrence time, the eruption shapes, the values of Psh and Porb, the amount of time spent at max and min, etc. I especially recommend IX Dra for now, though the observing seasons are long. These are stars for which even *snapshot* magntiudes are useful - though of course our main nutrient is long time series. I'm heading off to a conference in the Netherlands tomorrow night. Pretty sure I'll have email there, though. joe Oh, by the way, we have a big PASP paper which I believe will be accepted in the next 2 weeks: with coauthors Harvey, Fried, Rea, Monard, Cook, Skillman, Vanmunster, Bolt, McCormick, Krajci, Jensen, Gunn, Butterworth, Foote, Bos, Masi, and Warhurst. All-star cast! Contains results for *many* of our stars... with many more still in the hopper. We'll send a pdf file to authors, or a paper copy (send mailing address) if you request it. From jop at astro.columbia.edu Fri Jul 1 07:16:44 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 1 Jul 2005 07:16:44 -0400 (EDT) Subject: (cba:news) V4641 Sgr Message-ID: Oops, I forgot V4641 Sgr! Many of you know that this star went into a flaring state a couple weeks ago, then subsided, then came back... and who knows what it has up its sleeve for the future? Berto has been following it prodigiously, with good coverage also from Tom Richards and Peter Nelson. There's no mystery why the star is so popular - it's plenty bright and specializes in these huge (1 mag) flares, along with many more smaller ones. The reason I forget such a spectacular target is that I'm not quite sure how to use the data. Most of our projects involve discovery or tracking of a *period*. Periods are deep properties of a star, often revealing of the basic underlying dynamics (masses), or at least the classification and eruption patterns of the star. So we can make a lotta hay outa them! Flares are another story altogether. They jump up and tantalize you... and then you get your ruler out and try to measure the damn thing, amplitude, time, duration, whatever... and then another occurs, and then 20 more. And hardly ever can you find any pattern. The day will probably come when we understand such things, but it has not yet arrived. That's why I overlooked V4641 Sgr. But if everyone agreed with me, then we'd *certainly* never understand these flares - and they're admittedly very tantalizing. I'm just trying to make recommendations for projects which I think have a clear astrophysical goal, and (usually) that I'm personally interested in steering through to publication. That's a limited viewpoint... and once you have that camera in your hands, you're the boss of your local sky. With sometimes spectacular results, as the recent publicized successes of Berto, Jennie, and Tonny illustrate! joe From jop at astro.columbia.edu Thu Jul 7 06:27:14 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 7 Jul 2005 06:27:14 -0400 (EDT) Subject: (cba:news) no email access... Message-ID: Dear CBAers, I'm sorry to say I haven't managed to get email access here in Holland... and I'm not sure I'll have any for another 6 days. I wish I knew what was popping off up there! Anyway, I'll keep trying... feel free to jump in there and make your own invitations to campaign! joe From jop at astro.columbia.edu Thu Jul 7 06:31:01 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 7 Jul 2005 06:31:01 -0400 (EDT) Subject: (cba:news) [cvnet-outburst] ALERT: IL Vul extremely rare outburst (fwd) Message-ID: Dear CBAers, Well this looked awfully interesting to me - IL Vul - in my waning few minutes of email access. Probably a good northern target! joe ---------- Forwarded message ---------- Date: Sun, 3 Jul 2005 21:49:58 +0200 (CEST) From: Patrick Schmeer Reply-To: cvnet-outburst at yahoogroups.com To: cvnet-outburst at yahoogroups.com Cc: baavss-alert at yahoogroups.com Subject: [cvnet-outburst] ALERT: IL Vul extremely rare outburst Unfiltered CCD observations by P. Schmeer, Bischmisheim, Germany: VULIL 20050616.414 <175CR SPK VULIL 20050703.388 155CR SPK Instrument: University of Iowa, Rigel Telescope (0.37-m Cassegrain) Sequence: USNO-A2.0 catalogue (R magnitudes) Only one certain (1964) and two rather certain outbursts (1930, 1955) of this dwarf nova were observed before: 1930 Aug. 20, mag 15.5 1955 Sep. 22, mag 15 1964 Aug. 14.98 UT, mag 15 (JD 2438622.48, not 242...) (C. Hoffmeister, IBVS 80) On the outburst image I measured the following position: R.A. 20h38m32.72s Decl. +22o42'16.7" (J2000.0) Time-series photometry is very urgently required (perhaps also spectroscopy). Regards, Patrick ___________________________________________________________ Gesendet von Yahoo! Mail - Jetzt mit 1GB Speicher kostenlos - Hier anmelden: http://mail.yahoo.de Visit us on the web at http://cvnet.aavso.org Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/cvnet-outburst/ <*> To unsubscribe from this group, send an email to: cvnet-outburst-unsubscribe at yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ From jop at astro.columbia.edu Wed Jul 13 19:49:10 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 13 Jul 2005 19:49:10 -0400 (EDT) Subject: (cba:news) 2QZ0219-30 and SWIFT J1734-01 Message-ID: Dear CBAers, Back home now and able to read email. Whew. It'll take me a few days to study the recent data. But two things are clear... 1. Berto's discovery of superhumps in the new dwarf nova 2QZ0219-30 (also known as 2dF etc. and also as "For" in the Downes catalog) is quite important because of its location in/near the period gap. Let's track this guy around the Earth and as late as possible... even to quiescence in the (admittedly unlikely) event we can get that faint. A bright new superhumper, reaching 12th magnitude, near the Galactic pole and flirting with the period gap... this deserves a LOT of attention! 2. The new SWIFT transient - possibly a black-hole transient - is a very good target too. In 2000 a similar event occurred and Lew Cook found a 4-hour wave in the light curve, which turned out to be a superhump. A half-dozen stars have flashed similar things at us in the past, though never as well documented. It's likely that the amplitude will be low, or the period long (which might amount to the same thing, since you might see only a fraction of the amplitude)... but should yield a signal if one exists and if we can amass coverage over a wide range of longitudes. 3. Good time to quit on RX1730-05. This star is tough now, and it's time to quit. 4. Two northern dwarf novae, lightly observed and now possessing firm orbital periods (newly measured by John Thorstensen), are crying out for a superhump period measurement. (That's the faint wail you hear on a really quiet and dark night.) Yet they're SO lightly observed that we don't even know outburst recurrence periods... won't you please help us measure 'em? More in a few days, as I work though the data and messages... joe From jop at astro.columbia.edu Wed Jul 13 20:50:21 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 13 Jul 2005 20:50:21 -0400 (EDT) Subject: (cba:news) 2QZ0219-30 and SWIFT J1734-01 In-Reply-To: Message-ID: Oops! I forgot the names of those dwarf novae - that's V632 Cygni and V1006 Cygni. I'll prepare a more complete such list in a few days - but those are mighty timely. joe From jop at astro.columbia.edu Thu Jul 14 03:58:57 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 14 Jul 2005 03:58:57 -0400 (EDT) Subject: (cba:news) ATel 558. Daily Email Digest (fwd) Message-ID: Oops, another mistake. I misnamed the SWIFT transient - here's the correct name and coords (radio and optical are identical). Michel Bonnardeau writes that variations were <<0.1 mag on at least one night of observation - so this ain't a barnburner. Nevertheless, if you're a patient sort you might be able to tease a (true) variation out. The signal in KV UMa (the 2000 transient) was only 0.07 mag. But be warned - not one of our usual action-packed light curves! joe ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ The Astronomer's Telegram http://www.astronomerstelegram.org ------------------------------------------------------------------------------ Posted: Thu Jul 7 01:30:01 EDT 2005 -- Fri Jul 8 01:30:01 EDT 2005 ============================================================================== ATEL #558 ATEL #558 Title: Swift J1753.5-012: probable radio counterpart Author: Rob Fender (Southampton), Simon Garrington (Manchester), Tom Muxlow (Manchester) Queries: rpf at phys.soton.ac.uk Posted: 7 Jul 2005; 13:09 UT Subjects: Radio, Binaries, Black Holes, Neutron Stars, Transients We report the probable discovery of the radio counterpart to the new X-ray transient Swift J1753.5-0127 (ATEL#546,#547), in observations with the Multi-Element Radio-Linked Interferometer Network (MERLIN). MERLIN (+Lovell telescope) observed for ~8 hours on 2005 July 3, at 1.7 GHz, at the position of the optical counterpart reported by Halpern (ATEL#549). We detect a radio source at RA 17 53 28.29, Dec -01 27 06.22 (J2000, uncertainty of 50 milliarsec), consistent with the optical coordinates of Halpern, and also the revised Swift-UVOT coordinates reported by Still (ATEL#555). The measured flux density is 2.1 +/- 0.2 mJy. Subsequent MERLIN observations on 2005 July 4 and 5 indicate that this radio source is variable, strengthening the likely association with the X-ray transient. The images are consistent with a point source - there is no evidence in these preliminary analyses that the radio source is extended on angular scales greater than 350 milliarcsec. ------------------------------------------------------------------------------ Password Certification: Rob Fender (rpf at phys.soton.ac.uk) http://www.astronomerstelegram.org/?read=558 ============================================================================== From jop at astro.columbia.edu Thu Jul 14 21:13:42 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 14 Jul 2005 21:13:42 -0400 (EDT) Subject: (cba:news) IX Dra and MN Dra Message-ID: Dear CBAers, Reminder: we're starting up campaigns on IX Dra and MN Dra - time to get rolling on these tempting targets! Just in case you borealites are feeling forgotten! joe From jop at astro.columbia.edu Tue Jul 19 07:21:00 2005 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 19 Jul 2005 07:21:00 -0400 (EDT) Subject: (cba:news) new stars for july/aug Message-ID: Dear CBAers, Olde Whiteface is ravaging the sky again... and things are quiet on the dwarf-nova front... so let's make some adjustments! Plenty of good mysteries up there among the novalikes - and with the advantage that they can be studied closely in long campaigns, not subject to the up-and-down whims of eruptions. So strike 2qz 0219-30 from the menu (and likely your hearts), but keep a close eye on MN Dra and IX Dra in case they erupt. For the latter two, we want long-term light curves (including snapshot mags), as well as the long time series which are our primary calling card. But the long time series are likely to be of poor quality unless they erupt. V1494 Aql is still a good target from both hemispheres. In the south, I recommend RZ Gru and V345 Pav. We've tried RZ Gru before and not found much - but it's mighty bright and should give you excellent data, so we might just succeed on another try. V345 Pav is a little fainter but still feasible - a 4.75 hr eclipsing novalike which has been very little studied despite quite an intriguing orbital lightcurve. It's a good target, and might be a great one. In the north, I recommend MV Lyr. Another one we've tried before, with mixed results. We've found some periodic signals, but with questions about their stability; we really need to firm up the data base! In addition, V1494 Aql - and the Draco boys in case they erupt - are good menu items. joe