ALBERT

Description: On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meech, K J -- Ageorges, N -- A'Hearn, M F -- Arpigny, C -- Ates, A -- Aycock, J -- Bagnulo, S -- Bailey, J -- Barber, R -- Barrera, L -- Barrena, R -- Bauer, J M -- Belton, M J S -- Bensch, F -- Bhattacharya, B -- Biver, N -- Blake, G -- Bockelee-Morvan, D -- Boehnhardt, H -- Bonev, B P -- Bonev, T -- Buie, M W -- Burton, M G -- Butner, H M -- Cabanac, R -- Campbell, R -- Campins, H -- Capria, M T -- Carroll, T -- Chaffee, F -- Charnley, S B -- Cleis, R -- Coates, A -- Cochran, A -- Colom, P -- Conrad, A -- Coulson, I M -- Crovisier, J -- deBuizer, J -- Dekany, R -- de Leon, J -- Dello Russo, N -- Delsanti, A -- DiSanti, M -- Drummond, J -- Dundon, L -- Etzel, P B -- Farnham, T L -- Feldman, P -- Fernandez, Y R -- Filipovic, M D -- Fisher, S -- Fitzsimmons, A -- Fong, D -- Fugate, R -- Fujiwara, H -- Fujiyoshi, T -- Furusho, R -- Fuse, T -- Gibb, E -- Groussin, O -- Gulkis, S -- Gurwell, M -- Hadamcik, E -- Hainaut, O -- Harker, D -- Harrington, D -- Harwit, M -- Hasegawa, S -- Hergenrother, C W -- Hirst, P -- Hodapp, K -- Honda, M -- Howell, E S -- Hutsemekers, D -- Iono, D -- Ip, W-H -- Jackson, W -- Jehin, E -- Jiang, Z J -- Jones, G H -- Jones, P A -- Kadono, T -- Kamath, U W -- Kaufl, H U -- Kasuga, T -- Kawakita, H -- Kelley, M S -- Kerber, F -- Kidger, M -- Kinoshita, D -- Knight, M -- Lara, L -- Larson, S M -- Lederer, S -- Lee, C-F -- Levasseur-Regourd, A C -- Li, J Y -- Li, Q-S -- Licandro, J -- Lin, Z-Y -- Lisse, C M -- LoCurto, G -- Lovell, A J -- Lowry, S C -- Lyke, J -- Lynch, D -- Ma, J -- Magee-Sauer, K -- Maheswar, G -- Manfroid, J -- Marco, O -- Martin, P -- Melnick, G -- Miller, S -- Miyata, T -- Moriarty-Schieven, G H -- Moskovitz, N -- Mueller, B E A -- Mumma, M J -- Muneer, S -- Neufeld, D A -- Ootsubo, T -- Osip, D -- Pandea, S K -- Pantin, E -- Paterno-Mahler, R -- Patten, B -- Penprase, B E -- Peck, A -- Petitas, G -- Pinilla-Alonso, N -- Pittichova, J -- Pompei, E -- Prabhu, T P -- Qi, C -- Rao, R -- Rauer, H -- Reitsema, H -- Rodgers, S D -- Rodriguez, P -- Ruane, R -- Ruch, G -- Rujopakarn, W -- Sahu, D K -- Sako, S -- Sakon, I -- Samarasinha, N -- Sarkissian, J M -- Saviane, I -- Schirmer, M -- Schultz, P -- Schulz, R -- Seitzer, P -- Sekiguchi, T -- Selman, F -- Serra-Ricart, M -- Sharp, R -- Snell, R L -- Snodgrass, C -- Stallard, T -- Stecklein, G -- Sterken, C -- Stuwe, J A -- Sugita, S -- Sumner, M -- Suntzeff, N -- Swaters, R -- Takakuwa, S -- Takato, N -- Thomas-Osip, J -- Thompson, E -- Tokunaga, A T -- Tozzi, G P -- Tran, H -- Troy, M -- Trujillo, C -- Van Cleve, J -- Vasundhara, R -- Vazquez, R -- Vilas, F -- Villanueva, G -- von Braun, K -- Vora, P -- Wainscoat, R J -- Walsh, K -- Watanabe, J -- Weaver, H A -- Weaver, W -- Weiler, M -- Weissman, P R -- Welsh, W F -- Wilner, D -- Wolk, S -- Womack, M -- Wooden, D -- Woodney, L M -- Woodward, C -- Wu, Z-Y -- Wu, J-H -- Yamashita, T -- Yang, B -- Yang, Y-B -- Yokogawa, S -- Zook, A C -- Zauderer, A -- Zhao, X -- Zhou, X -- Zucconi, J-M -- New York, N.Y. -- Science. 2005 Oct 14;310(5746):265-9. Epub 2005 Sep 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Astronomy, University of Hawaii at Manoa, 2680 Woodlawn Drive, Honolulu, HI 96822, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16150977" target="_blank"〉PubMed〈/a〉

Description: Star-like objects with effective temperatures of less than 2,700 kelvin are referred to as 'ultracool dwarfs'. This heterogeneous group includes stars of extremely low mass as well as brown dwarfs (substellar objects not massive enough to sustain hydrogen fusion), and represents about 15 per cent of the population of astronomical objects near the Sun. Core-accretion theory predicts that, given the small masses of these ultracool dwarfs, and the small sizes of their protoplanetary disks, there should be a large but hitherto undetected population of terrestrial planets orbiting them--ranging from metal-rich Mercury-sized planets to more hospitable volatile-rich Earth-sized planets. Here we report observations of three short-period Earth-sized planets transiting an ultracool dwarf star only 12 parsecs away. The inner two planets receive four times and two times the irradiation of Earth, respectively, placing them close to the inner edge of the habitable zone of the star. Our data suggest that 11 orbits remain possible for the third planet, the most likely resulting in irradiation significantly less than that received by Earth. The infrared brightness of the host star, combined with its Jupiter-like size, offers the possibility of thoroughly characterizing the components of this nearby planetary system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Gillon, Michael -- Jehin, Emmanuel -- Lederer, Susan M -- Delrez, Laetitia -- de Wit, Julien -- Burdanov, Artem -- Van Grootel, Valerie -- Burgasser, Adam J -- Triaud, Amaury H M J -- Opitom, Cyrielle -- Demory, Brice-Olivier -- Sahu, Devendra K -- Bardalez Gagliuffi, Daniella -- Magain, Pierre -- Queloz, Didier -- England -- Nature. 2016 May 2;533(7602):221-4. doi: 10.1038/nature17448.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout 19C, 4000 Liege, Belgium. ; NASA Johnson Space Center, 2101 NASA Parkway, Houston, Texas, 77058, USA. ; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. ; Center for Astrophysics and Space Science, University of California San Diego, La Jolla, California 92093, USA. ; Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK. ; Astrophysics Group, Cavendish Laboratory, 19 J J Thomson Avenue, Cambridge, CB3 0HE, UK. ; Indian Institute of Astrophysics, Koramangala, Bangalore 560 034, India.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27135924" target="_blank"〉PubMed〈/a〉

Description: We present optical and UV analysis of the luminous Type Ia supernova SN 2012dn covering the period from ~–11 to +109 d with respect to the B -band maximum, which occurred on JD 245 6132.89 ± 0.19, with an apparent magnitude of $m_{B}^{\rm max}$  = 14.38 ± 0.02. The absolute magnitudes at maximum in B and V bands are $M_{B}^{\rm max} = -19.52 \pm 0.15$ and $M_{V}^{\rm max} = -19.42 \pm 0.15$ , respectively. SN 2012dn is marginally luminous compared to normal Type Ia supernovae. The peak bolometric luminosity of $\log L_{\rm bol}^{\rm max} = 43.27 \pm 0.06$ erg s –1 suggests that 0.82 ± 0.12 M of 56 Ni was synthesized in the explosion. The decline rate m 15 ( B ) true = 0.92 ± 0.04 mag is lower than that of normal Type Ia supernovae, and similar to the luminous SN 1991T. However, the photometric and spectroscopic behaviour of SN 2012dn is different from that of SN 1991T. Early-phase light curves in R and I bands are very broad. The I -band peak has a plateau-like appearance similar to the super- Chandra SN 2009dc. Pre-maximum spectra show clear evidence of C ii 6580 Å line, indicating the presence of unburned materials. The velocity evolution of C ii line is peculiar. Except for the very early phase (~–13 d), the C ii line velocity is lower than the velocity estimated using the Si ii line. During the pre-maximum and close to the maximum phase, to reproduce observed shape of the spectra, the synthetic spectrum code syn++ needs significantly higher blackbody temperature than those required for normal Type Ia events. The photospheric velocity evolution and other spectral properties are similar to those of the carbon-rich SN 2006gz.

Description: We present optical UBVRI photometry and medium-resolution spectroscopy of a transitional Type Ia supernova, SN 2009an, over the period –6 to ~+150 d from the B maximum. With a m 15 ( B ) = 1.514 ± 0.132, SN 2009an declines faster than normal Type Ia events, but slower than the fast-declining, low-luminosity 1991bg-like events. The B -band absolute magnitude at maximum is –19.02 ± 0.20. The peak bolometric luminosity indicates that 0.41 M of 56 Ni was synthesized during the explosion. The pre-maximum and early post-maximum spectral evolution of SN 2009an is very similar to that in the transitional Type Ia SN 2004eo. High-velocity features in the Ca ii near-infrared triplet are seen during the early phases. Similar to the other few objects belonging to this class, SN 2009an exhibits a higher value (~0.4) of the Si ii line ratio R (Si ii ). The velocity gradient of the Si ii 6355 Å line in the post-maximum epoch ( $\dot{v} = 60$ km s –1 d –1 ) is at the boundary between the low-velocity-gradient and high-velocity-gradient groups.

Description: Optical and NIR observations of the Type Ia supernova SN 2014J in M82 are presented. The observed light curves are found to be similar to normal Type Ia supernovae (SNe Ia), with a decline rate parameter m 15 ( B ) = 1.08 ± 0.03. The supernova reached B -band maximum on JD 2456690.14, at an apparent magnitude m B (max) = 11.94. The optical spectra show a red continuum with deep interstellar Na i absorption, but otherwise resemble those of normal SNe Ia. The Si ii 6355 feature indicates a velocity of ~12 000 km s –1 at B -band maximum, which places SN 2014J at the border of the normal velocity and high velocity group of SNe Ia. The velocity evolution of SN 2014J places it in the Low Velocity Gradient subclass, whereas the equivalent widths of Si ii features near B -band maximum place it at the border of the core normal and Broad Line subclasses of SNe Ia. An analytic model fit to the bolometric light curve indicates that a total of ~1.3 M was ejected in the explosion, and the ejected 56 Ni mass M Ni  ~ 0.6 M . The low [Fe iii ] 4701 to [Fe ii ] 5200 ratio in the nebular spectra of SN 2014J hints towards clumpiness in the ejecta. Optical broad-band, linear polarimetric observations of SN 2014J obtained on four epochs indicate an almost constant polarization ( P R  ~2.7 per cent;  ~ 37°), which suggests that the polarization signal is of interstellar origin.

Description: We present optical UBVRI photometry and medium resolution spectroscopy of the Type Ib supernova iPTF13bvn, spanning a phase of ~–13 d to +71 d with respect to B -band maximum. The post-maximum decline rates indicate a fast decline with m 15 ( B ) = 1.82. Correcting for a Galactic extinction E ( B – V ) MW  = 0.045 and host galaxy extinction of E ( B – V ) host  = 0.17, the absolute V -band magnitude peaks at M V  = –17.23 ± 0.20. The bolometric light curve indicates that ~0.09 M of 56 Ni was synthesized in the explosion. The earliest spectrum (–13 d) shows the presence of He i 5876 Å feature at a velocity of ~15 000 km s –1 , which falls rapidly by the time the SN approaches the epoch of B -band maximum. The photospheric velocity near maximum light, as indicated by the Fe ii 5169 Å feature, is ~9000 km s –1 . The estimate for the 56 Ni mass, together with the estimates for the ejected mass ( M ej ) and kinetic energy of the explosion ( E k ) indicate that iPTF13bvn is a low-luminosity Type Ib supernova, with a lower than average ejected mass and kinetic energy. Our results suggest that the progenitor of iPTF13bvn is inconsistent with a single Wolf–Rayet star.

Description: We present the low-resolution spectroscopic and UBVRI broad-band photometric investigations of the Type IIb supernova (SN) 2011fu, discovered in UGC 01626. The photometric follow-up of this event was initiated a few days after the explosion and covers a period of about 175 d. The early-phase light curve shows a rise, followed by steep decay in all bands, and shares properties very similar to that seen for SN 1993J, with a possible detection of the adiabatic cooling phase. Modelling of the quasi-bolometric light curve suggests that the progenitor had an extended (~1  x 10 13 cm), low-mass (~0.1 M ) H-rich envelope on top of a dense, compact (~2  x 10 11 cm), more massive (~1.1 M ) He-rich core. The nickel mass synthesized during the explosion was found to be ~0.21 M , slightly larger than that seen for other Type IIb SNe. The spectral modelling performed with synow suggests that the early-phase line velocities for H and Fe ii features were ~16 000 and ~14 000 km s –1 , respectively. Then, the velocities declined up to day +40 and became nearly constant at later epochs.

Description: Optical UBVRI photometry and low-resolution spectroscopy of the Type IIb supernova SN 2011dh in M51 are presented, covering the first year after the explosion. The light curve and spectral evolution are discussed. The early phase light-curve evolution of SN 2011dh is very similar to SN 1993J and SN 2008ax. In the late phase, however, SN 2011dh declines faster than SN 1993J. The late phase decline in the B band is steeper than in the R and I bands, indicating the possibility of dust formation. With a peak V -band absolute magnitude of M V  = –17.123 ± 0.18 mag, SN 2011dh is a marginally faint type IIb event. The reddening corrected colour curves of SN 2011dh are found to be redder than other well-studied Type IIb supernovae. The bolometric light curve indicates ~0.09 M of 56 Ni is synthesized during the explosion. The He i lines were detected in the spectra during the rise to maximum. The nebular spectra of SN 2011dh show a box-shaped emission in the red wing of the [O i ] 6300–6363 Å feature, that is attributed to Hα emission from a shock-excited circumstellar material. The analysis of nebular spectra indicates that ~0.2 M of oxygen was ejected during the explosion. Further, the [Ca ii ]/[O i ] line ratio in the nebular phase is ~0.7, indicating a progenitor with a main-sequence mass of 10–15 M .

Description: We present a study of the properties of star-forming regions within a sample of seven Wolf–Rayet (WR) galaxies. We analyse their morphologies, colours, star-formation rates (SFRs), metallicities and stellar populations, combining broad-band and narrow-band photometry with low-resolution optical spectroscopy. The UBVRI observations were made with the 2-m HCT (Himalayan Chandra Telescope) and 1-m ARIES telescope. The spectroscopic data were obtained using the Hanle Faint Object Spectrograph Camera (HFOSC) mounted on the 2-m HCT. The observed galaxies are NGC 1140, IRAS 07164+5301, NGC 3738, UM 311, NGC 6764, NGC 4861 and NGC 3003. The optical spectra were used to search for the faint WR features, to confirm that the ionization of the gas is caused by the massive stars, and to quantify the oxygen abundance of each galaxy using several independent empirical calibrations. We detected broad features originating in WR stars in NGC 1140 and 4861 and used them to derive the massive star populations. For these two galaxies we also derived the oxygen abundance using a direct estimation of the electron temperature of the ionized gas. The N/O ratio in NGC 4861 is ~0.25–0.35 dex higher than expected, which may be a consequence of the chemical pollution by N-rich material released by WR stars. Using our Hα images we identified tens of star-forming regions within these galaxies, for which we derived the SFR. Our Hα-based SFR usually agrees with the SFR computed using the far-infrared and the radio-continuum flux. For all regions we found that the most recent star-formation event is 3–6 Myr old. We used the optical broad-band colours in combination with Starburst99 models to estimate the internal reddening and the age of the dominant underlying stellar population within all these regions. Knots in NGC 3738, 6764 and 3003 generally show the presence of an important old (400–1000 Myr) stellar population. However, the optical colours are not able to detect stars older than 20–50 Myr in the knots of the other four galaxies. This fact suggests that both the current intensity of the starbursts and the star-formation activity have been ongoing for at least a few tens of millions of years in these objects.