%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Supernova 2002ap in M74 Supernova 2002ap was discovered in M74 on January 29, 2002 by Japanese amateur astronomer Yoji Hirose, 258" west and 108" south of the center of that galaxy, at mag 14.5, rising a day later to 13.7, 13.4 on January 31, 12.5 on February 3, 12.4 on February 4, and still brightening! The type of this supernova has been preliminarily determined as type Ib/c. Its spectrum shows peculiar features; this brings up evidence that this object may be a hypernova (super-luminous supernova, up to 100 times brighter than "normal" supernovae of type Ia, occurring when very massive stars explode at the end of their nuclear lives; the SN 2002ap progenitor star has been estimated at at least 40 solar masses). Radio radiation of the supernova was discovered very early, on February 1. It will be most interesting to observe the development of this object at all wavelengths. This supernova was definitely discovered before its maximum. From February 5 to 12, it was observed at a maximal brightness of 12.3 mag, then declined. It was suspected that this object may be accompanied by a Gamma Ray Burst in the very near future .. this would be by far the nearest such event observed yet. .. this is still a developing story, and thrilling! The image in the page was obtained on January 31, 2002 from Mt. Hopkins, Arizona with the 1.2m telescope by Harvard CfA astronomers. Click to see it compared to a Digital Sky Survey comparison image. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Circular No. 7810 2002 January 30 (7810) Daniel W. E. Green Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304 Phone 617-495-7440/7244/7444 (for emergency use only) SUPERNOVA 2002ap IN M74 S. Nakano, Sumoto, Japan, reports the discovery by Yoji Hirose, Chigasaki, Kanagawa-ken, of an apparent supernova (V = 14.5) on five unfiltered CCD frames (limiting mag 17) taken on Jan. 29.398-29.501 UT with a 0.25-m f/6.3 Schmidt-Cassegrain reflector. Hirose reported the new object as being 274" west and 93" south of the center of M74 (= NGC 628). Nothing was visible at this location on his CCD frames taken on Jan. 3. R. Kushida, Yatsugatake South Base Observatory, reports the following precise position (measured by Y. Kushida) for SN 2002ap from an unfiltered CCD image taken on Jan. 30.382, with the star at mag 13.7: R.A. = 1h36m23s.85, Decl. = +15o45'13".2 (equinox 2000.0), or 258" west and 108" south of the center of M74. No star is visible at this position on Kushida's survey frames taken from 1994 to 2001 Dec. 18 (limiting mag 17-18). W. Li, University of California, reports that an image taken with the Katzman Automatic Imaging Telescope (KAIT) on Jan. 29.2 showed the new object at mag 14.4. Li also measured position end figures for SN 2002ap: 23s.87, 13".0. A KAIT image taken on Jan. 25.2 showed nothing at this position (limiting mag about 18.0). %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% iauc 7811 2002 January 31 (7811) Daniel W. E. Green SUPERNOVA 2002ap IN M74 K. Kinugasa and H. Kawakita, Gunma Astronomical Observatory (GAO); K. Ayani and T. Kawabata, Bisei Astronomical Observatory (BAO); and H. Yamaoka, Kyushu University, write: "Low-resolution spectra of SN 2002ap (IAUC 7810) were obtained on Jan. 31.4 UT with the GAO 0.65-m telescope (+ GCS; range 380-750 nm) and on Jan. 31.5 with the BAO 1.01-m telescope (range 470-700 nm). Preliminary reduction reveals a rather blue continuum with a steep decrease over 650-700 nm, without any deep absorption or emission. Very broad (FWZI about 30-50 nm) and shallow depressions exist around 470, 570 (deepest), and 620 nm. The overall features resemble that of the peculiar type-Ib/c supernova (or 'hypernova') 1997ef, but SN 2002ap is much bluer." P. Meikle and L. Lucy, Imperial College, London; S. Smartt, Institute of Astronomy, Cambridge; B. Leibundgut, European Southern Observatory; and P. Lundqvist, Stockholm Observatory, report that R. Ostensen obtained a spectrum (range 432.6-789.9 nm) of SN 2002ap at the William Herschel Telescope on Jan. 30.9 UT: "The spectrum shows a blue continuum with broad absorption features at about 448.0, 557.5, and 719.5 nm. The red absorption is particularly broad, spanning approximately 660-760 nm. The absorption features bear some resemblance to those seen in SN 1998bw at 7 days (Stathakis et al. 2000, MNRAS 314, 807), though shifted further to the blue in SN 2002ap by 15 000-20 000 km/s. The 448.0-nm absorption appears to be deeper and may include a more narrow component than in SN 1998bw. The emission peak at 530 nm for SN 1998bw is absent in the spectrum of SN 2002ap. We suggest that SN 2002ap may be a younger and/or more energetic version of SN 1998bw." A. Gal-Yam and O. Shemmer, Tel Aviv University, report: "A spectrum (range 400-780 nm) of SN 2002ap was obtained with the Wise Observatory 1-m telescope (+ FOSC spectrograph) on Jan. 31 by J. Dann. The object was very bright, and the high S/N spectrum shows a very blue continuum with broad features around 400 and 500 nm, a steep decline (of about a factor of 3 in flux) from 500 nm to 700 nm, and a broad hump around 600 nm superposed on the blue continuum. A hint of a rise toward the red end of the spectrum, at 780 nm, is also evident. Overall, the spectrum is markedly similar to spectra of the peculiar type-Ic supernova 1998bw obtained before maximum light (e.g., Patat et al. 2001, Ap.J. 555, 900). In view of the peculiar properties of this object, as well as the possible connection of SN 1998bw with GRB 980425, we urge further observations at all wavelengths." %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% iauc 7816 2002 February 2 (7816) Daniel W. E. Green SUPERNOVA 2002ap IN M74 S. Smartt and E. Ramirez-Ruiz, Institute of Astronomy, Cambridge; and P. Vreeswijk, University of Amsterdam, report that 120-s UBVI images of M74 were taken with the Isaac Newton Telescope (+ Wide Field Camera) in July 2001, as part of the INT Wide Field Survey. They detect an object with B = 21.6, V = 21.2, I = 20.5 (uncertainties +/- 0.2 mag) at R.A. = 1h36m24s.00, Decl. = +15o45'13".6 (equinox 2000.0), which is within 1".3 of a radio source found on Feb. 1.03 UT (cf. http://gcn.gsfc.nasa.gov/gcn/gcn3/1237.gcn3; position end figures 23s.920, 12".87). This fairly faint object shows some inconclusive evidence of being extended; at the spatial resolution of the images (about 50 pc), the object could be an unresolved small cluster or H II region, or a predominantly bright star on a variable background. Assuming that it is a single star, with a distance modulus of 29.5 to M74, they estimate absolute magnitudes M_B = -8.2, M_V = -8.5, M_I = -9.1. The colors B-V = +0.3, V-I = +0.6, and these absolute magnitudes are consistent with a very luminous early- to mid-F-type supergiant. The bolometric luminosity is approximately 10**5.3 solar luminosities, which would place the star in the luminous-blue-variable region of the HR diagram (Humphreys and Davidson 1994, PASP 106, 1025) and suggests an initial mass of around 40 solar masses. Smartt et al. add that any significant extinction would make the star intrinsically bluer and more luminous. Further astrometry and image-shape analysis are required to confirm that the progenitor object is stellar, and monitoring of SN 2002ap at all wavelengths is encouraged. Visual magnitude estimates: Jan. 31.784 UT, 13.2 (L. Brat, Pec pod Snezkou, Czech Republic); Feb. 2.776, 12.7 (R. J. Bouma, Groningen, The Netherlands); 2.783, 12.6 (K. Hornoch, Lelekovice, Czech Republic). %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% iauc 7817 2002 February 4 (7817) SUPERNOVA 2002ap IN M74 E. Berger, S. R. Kulkarni, and D. A. Frail, California Institute of Technology, report that an observation of SN 2002ap with the Very Large Array at 8.46 GHz on Feb. 1.03 UT reveals a radio source with a flux density of 375 +/- 30 microJy coincident with the supernova (IAUC 7816; GCN Circ. No. 1237): "The radio emission peaks at approximately 5 GHz and appears to be fading with flux densities in the 8.46-GHz band of 255 +/- 44 microJy on Feb. 1.93 and 201 +/- 47 microJy on Feb. 2.79. SN 2002ap is thus > 3 orders of magnitude less luminous in the radio band than SN 1998bw." %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% iauc 7820 2002 February 5 (7820) SUPERNOVA 2002ap IN M74 S. Mattila and P. Meikle, Imperial College, London, report that SN 2002ap continues to brighten in the infrared, as indicated by the following magnitudes from observations obtained by K. Chambers (Institute for Astronomy, University of Hawaii) at the U.K. Infrared Telescope (+ infrared imager UFTI): Feb. 3.2 UT, I = 12.62, Z = 12.44, J = 12.39, H = 12.23, K = 12.20; 4.2, 12.51, 12.30, 12.27, 12.08, 11.94. L. Wang, Lawrence Berkeley National Laboratory; D. Baade, European Southern Observatory (ESO); C. Fransson, Stockholm Observatory; P. Hoeflich, University of Texas; P. Lundqvist, Stockholm Observatory; and J. C. Wheeler, University of Texas, report that high-quality spectropolarimetry (range 350-860 nm; spectral resolution 1.27 nm and 0.265 nm/pixel) of SN 2002ap was obtained with the ESO Very Large Telescope UT3 (+ FORS1) on Feb. 3 UT. A broad spectral absorption feature at 650-800 nm (which, if due to the Ca II infrared triplet, implies an expansion velocity of order 45 000 km/s) shows a degree of polarization distinctively different from other parts of the observed spectrum. The degree of polarization of this feature peaks at 735.1 nm (with FWHM = 64.3 nm) and differs by > 1.1 percent when compared to neighboring wavelength regions. As the contribution from interstellar dust is uncertain, the observed 1.1-percent difference should be regarded as a lower limit to the polarization intrinsic to the supernova and implies the presence of significantly asymmetric ejecta. Further spectropolarimetric observations are encouraged. P. Vreeswijk, University of Amsterdam; and S. Smartt, Institute of Astronomy, Cambridge, report that images taken by G. Gilmore and R. Wyse on the Isaac Newton Telescope at La Palma on Feb. 2.9 UT have allowed an accurate projection of the position of SN 2002ap onto the prediscovery images reported on IAUC 7816: "Within the new errors, the supernova is not coincident with the V= 21.2 object reported as a possible progenitor. The difference in position between SN 2002ap and this object is 1".7 +/- 0".3, where the error is dominated by the error in the position of the faint object, indicating that this was a chance alignment. There is no object in the prediscovery images at the supernova position, to limiting (5-sigma, 2" aperture radius) magnitudes of U = 20.8, B = 22.1, V = 22.0, I = 20.8." W. Hasubick, Buchloe, Germany, reports that CCD frames taken on Jan. 4.795 UT show nothing at the position of SN 2002ap (limiting red mag 18.5). CCD R magnitudes by K. Hornoch, Lelekovice, Czech Republic: Jan. 31.808 UT, 13.04; Feb. 2.764, 12.66; 3.749, 12.53. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% iauc 7821 2002 February 6 (7821) SUPERNOVA 2002ap IN M74 P. Rodriguez Pascual, R. Gonzalez Riestra, B. Gonzalez Garcia, M. Santos Lleo, M. Guainazzi, and N. Schartel, XMM-Newton Science Operations Centre, European Space Agency, write that XMM-Newton observed the location of SN 2002ap from Feb. 3.00 to 3.40 UT. SN 2002ap appears in the OM UVW1 images (wavelength range 245-320 nm) with a brightness of 14.4 counts/s, which corresponds to a flux of 7 x 10**-15 erg cm**-2 s**-1 A**-1. Preliminary analysis of the EPIC-pn image shows a 3.5-sigma excess of photons that is located at a distance of 4" with respect to the position given on IAUC 7810. This excess corresponds to a countrate of 9.0 (+/- 2.5) x 10**-4 count/s. At this stage of data reduction, the ultraviolet position error is expected to be < 10". %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% iauc 7822 2002 February 9 (7822) SUPERNOVA 2002ap IN M74 S. Smartt, Institute of Astronomy, Cambridge; and P. Meikle, Imperial College, London, write: "A spectrum (range 569-610 nm; resolution 0.08 nm) of SN 2002ap, obtained with the William Herschel Telescope at La Palma on Feb. 2.9 UT by C. Benn, shows absorption features of the interstellar-medium lines Na I (588.995 and 589.592 nm) shifted by +631 km/s. This matches the redshift of M74 and confirms that SN 2002ap is indeed associated with that host galaxy. We see no higher redshifted components in this spectrum (continuum signal-to-noise = 130), which suggests that SN 2002ap is not behind M74 in an unassociated galaxy." NGC 628 = M74 heliocentric velocity from lines in sn spectra +631 km/s iauc 7822 S. Smartt & P. Meikle from Leda in radio +656 km/s from Leda in optical +639 km/s from Leda mean +656 km/s Foreground extinction in B from Leda/Schlegel 0.30 E(B-V)=.30/4 0.075 E(B-V)=.30/4.1 0.073 See Cardelli p. 249 Paolo E(B-V) 0.08 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% still restricted %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Circular No. 7835 2002 February 22 (7835) Daniel W. E. Green SUPERNOVA 2002ap IN M74 K. S. Kawabata, G. Kosugi, T. Sasaki, Y. Ohyama, N. Kashikawa, Y. Saito, and M. Iye, National Astronomical Observatory of Japan; and K. Nomoto, University of Tokyo, write: "We carried out sequential optical spectropolarimetry (range 385-830 nm; resolution 0.56 nm and 0.14 nm/pixel) of SN 2002ap (IAUC 7810) on Feb. 9.24, 10.28, 11.26 and 12.26 UT with the Subaru 8.2-m telescope (+ FOCAS). The polarization bump corresponding to the broad absorption feature in the wavelength range 650-800 nm (cf. IAUC 7820) was still prominent, but the wavelength of the maximum polarization had shifted to 748 nm and the FWHM of the feature had narrowed to 45 nm. A significant variation in the position angle of the polarization with respect to wavelength was observed around this feature. The position angle showed a broad dip of about 15 deg over the feature at 650-800 nm, superposed on a local (720-770 nm) asymmetric bump of 20 deg in height that peaked at 760 nm. These findings suggest a complicated asymmetric geometry of the explosion." Copyright 2002 CBAT 2002 February 22 (7835) Daniel W. E. Green %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%