Browsing by Author "Soszynski, I"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    OGLE-2013-BLG-0911Lb : A Secondary on the Brown-dwarf Planet Boundary around an M Dwarf
    (2020) Miyazaki, S; Sumi, T; Bennett, DP; Udalski, A; Shvartzvald, Y; Street, R; Bozza, V; Yee, JC; Rabus, Markus; D'Ago, Giuseppe; Bond, IA; Rattenbury, N; Koshimoto, N; Suzuki, D; Fukui, A; Abe, F; Bhattacharya, A; Barry, R; Donachie, M; Fujii, H; Hirao, Y; Itow, Y; Kamei, Y; Kondo, I; Li, MCA; Ling, CH; Matsubara, Y; Matsuo, T; Muraki, Y; Nagakane, M; Ohnishi, K; Ranc, C; Saito, T; Sharan, A; Shibai, H; Suematsu, H; Sullivan, DJ; Tristram, PJ; Yamakawa, T; Yonehara, A; Skowron, J; Poleski, R; Mroz, P; Szymanski, MK; Soszynski, I; Pietrukowicz, Pawel; KozLowski, S; Ulaczyk, K; Wyrzykowski, L; Friedmann, M; Kaspi, S; Maoz, D; Albrow, M; Christie, G; DePoy, DL; Gal-Yam, A; Gould, A; Lee, CU; Manulis, I; McCormick, J; Natusch, T; Ngan, H; Pogge, RW; Porritt, I; Tsapras, Y; Bachelet, E; Hundertmark, MPG; Dominik, M; Bramich, DM; Cassan, A; Jaimes, RF; Horne, K; Schmidt, R; Snodgrass, C; Wambsganss, J; Steele, IA; Menzies, J; Mao, S; Jorgensen, UG; Burgdorf, MJ; Ciceri, S; Novati, SC; Evans, DF; Hinse, TC; Kains, N; Kerins, E; Korhonen, H; Mancini, L; Popovas, A; Rahvar, S; Scarpetta, G; Skottfelt, J; Southworth, J; Peixinho, N; Verma, P
  • No Thumbnail Available
    Item
    Photometric and spectroscopic evolution of the interacting transient AT 2016jbu(Gaia16cfr)
    (2022) Brennan, S. J.; Fraser, M.; Johansson, J.; Pastorello, A.; Kotak, R.; Stevance, H. F.; Chen, T-W; Eldridge, J. J.; Bose, S.; Brown, P. J.; Callis, E.; Cartier, R.; Dennefeld, M.; Dong, Subo; Duffy, P.; Elias-Rosa, N.; Hosseinzadeh, G.; Hsiao, E.; Kuncarayakti, H.; Martin-Carrillo, A.; Monard, B.; Nyholm, A.; Pignata, G.; Sand, D.; Shappee, B. J.; Smartt, S. J.; Tucker, B. E.; Wyrzykowski, L.; Abbot, H.; Benetti, S.; Bento, J.; Blondin, S.; Chen, Ping; Delgado, A.; Galbany, L.; Gromadzki, M.; Gutierrez, C. P.; Hanlon, L.; Harrison, D. L.; Hiramatsu, D.; Hodgkin, S. T.; Holoien, T. W-S; Howell, D. A.; Inserra, C.; Kankare, E.; Kozlowski, S.; Muller-Bravo, T. E.; Maguire, K.; McCully, C.; Meintjes, P.; Morrell, N.; Nicholl, M.; O'Neill, D.; Pietrukowicz, P.; Poleski, R.; Prieto, J. L.; Rau, A.; Reichart, D. E.; Schweyer, T.; Shahbandeh, M.; Skowron, J.; Sollerman, J.; Soszynski, I; Stritzinger, M. D.; Szymanski, M.; Tartaglia, L.; Udalski, A.; Ulaczyk, K.; Young, D. R.; van Leeuwen, M.; van Soelen, B.
    We present the results from a high-cadence, multiwavelength observation campaign of AT 2016jbu (aka Gaia16cfr), an interacting transient. This data set complements the current literature by adding higher cadence as well as extended coverage of the light-curve evolution and late-time spectroscopic evolution. Photometric coverage reveals that AT 2016jbu underwent significant photometric variability followed by two luminous events, the latter of which reached an absolute magnitude of M-V similar to-18.5 mag. This is similar to the transient SN 2009ip whose nature is still debated. Spectra are dominated by narrow emission lines and show a blue continuum during the peak of the second event. AT 2016jbu shows signatures of a complex, non-homogeneous circumstellar material (CSM). We see slowly evolving asymmetric hydrogen line profiles, with velocities of 500 km s(-)(1) seen in narrow emission features from a slow-moving CSM, and up to 10 000 km s(-1) seen in broad absorption from some high-velocity material. Late-time spectra (similar to+1 yr) show a lack of forbidden emission lines expected from a core-collapse supernova and are dominated by strong emission from H, He I, and Ca II. Strong asymmetric emission features, a bumpy light curve, and continually evolving spectra suggest an inhibit nebular phase. We compare the evolution of H alpha among SN 2009ip-like transients and find possible evidence for orientation angle effects. The light-curve evolution of AT 2016jbu suggests similar, but not identical, circumstellar environments to other SN 2009ip-like transients.
  • No Thumbnail Available
    Item
    Progenitor, environment, and modelling of the interacting transient AT 2016jbu (Gaia16cfr)
    (2022) Brennan, S. J.; Fraser, M.; Johansson, J.; Pastorello, A.; Kotak, R.; Stevance, H. F.; Chen, T-W; Eldridge, J. J.; Bose, S.; Brown, P. J.; Callis, E.; Cartier, R.; Dennefeld, M.; Dong, Subo; Duffy, P.; Elias-Rosa, N.; Hosseinzadeh, G.; Hsiao, E.; Kuncarayakti, H.; Martin-Carrillo, A.; Monard, B.; Pignata, G.; Sand, D.; Shappee, B. J.; Smartt, S. J.; Tucker, B. E.; Wyrzykowski, L.; Abbot, H.; Benetti, S.; Bento, J.; Blondin, S.; Chen, Ping; Delgado, A.; Galbany, L.; Gromadzki, M.; Gutierrez, C. P.; Hanlon, L.; Harrison, D. L.; Hiramatsu, D.; Hodgkin, S. T.; Holoien, T. W-S; Howell, D. A.; Inserra, C.; Kankare, E.; Kozlowski, S.; Muller-Bravo, T. E.; Maguire, K.; McCully, C.; Meintjes, P.; Morrell, N.; Nicholl, M.; O'Neill, D.; Pietrukowicz, P.; Poleski, R.; Prieto, J. L.; Rau, A.; Reichart, D. E.; Schweyer, T.; Shahbandeh, M.; Skowron, J.; Sollerman, J.; Soszynski, I; Stritzinger, M. D.; Szymanski, M.; Tartaglia, L.; Udalski, A.; Ulaczyk, K.; Young, D. R.; van Leeuwen, M.; van Soelen, B.
    We present the bolometric light curve, identification and analysis of the progenitor candidate, and preliminary modelling of AT 2016jbu (Gaia16cfr). We find a progenitor consistent with a similar to 22-25 M-circle dot yellow hypergiant surrounded by a dusty circumstellar shell, in agreement with what has been previously reported. We see evidence for significant photometric variability in the progenitor, as well as strong H alpha emission consistent with pre-existing circumstellar material. The age of the environment, as well as the resolved stellar population surrounding AT 2016jbu, supports a progenitor age of >10 Myr, consistent with a progenitor mass of similar to 22 M-circle dot. A joint analysis of the velocity evolution of AT 2016jbu and the photospheric radius inferred from the bolometric light curve shows the transient is consistent with two successive outbursts/explosions. The first outburst ejected material with velocity similar to 650 km s(-1), while the second, more energetic event ejected material at similar to 4500 km s(-1). Whether the latter is the core collapse of the progenitor remains uncertain. We place a limit on the ejected Ni-56 mass of <0.016 M-circle dot. Using the Binary Population And Spectral Synthesis (BPASS) code, we explore a wide range of possible progenitor systems and find that the majority of these are in binaries, some of which are undergoing mass transfer or common-envelope evolution immediately prior to explosion. Finally, we use the SuperNova Explosion Code (SNEC) to demonstrate that the low-energy explosions within some of these binary systems, together with sufficient circumstellar material, can reproduce the overall morphology of the light curve of AT 2016jbu.
  • No Thumbnail Available
    Item
    The Araucaria Project
    (2004) Gieren, W; Pietrzynski, G; Walker, A; Bresolin, F; Minniti, D; Kudritzki, RP; Udalski, A; Soszynski, I; Fouqué, P; Storm, J; Bono, G
    In a previous paper, we reported on the discovery of more than a hundred new Cepheid variables in the Sculptor Group spiral galaxy NGC 300 from wide-field images taken in the B and V photometric bands at ESO/La Silla. In this paper, we present additional VI data, derive improved periods and mean magnitudes for the variables, and construct period-luminosity relations in the V, I, and the reddening-independent V - I Wesenheit bands using 58 Cepheid variables with periods between 11 and 90 days. We obtain tightly defined relations, and by fitting the slopes determined for the LMC Cepheids by the OGLE II Project we obtain reddening-corrected distances to the galaxy in all bands, which show a slight offset to each other in the sense that the Wesenheit relation yields the smallest distance, whereas the I- and V-band distances are larger by 0.094 and 0.155 mag, respectively. We adopt as our best value the distance derived from the reddening-free Wesenheit magnitudes, which is 26.43 +/- 0.04( random) +/- 0.05( systematic) mag. The distance moduli from both the V and I bands agree perfectly with the Wesenheit value if one assumes an additional reddening of E( B - V) = 0.05 mag intrinsic to NGC 300, in addition to the Galactic foreground reddening toward NGC 300 of 0.025 mag. Such a modest intrinsic reddening is supported by recent Hubble Space Telescope (HST) images of NGC 300, which show that this galaxy is relatively dustfree but also reveal that there must be some dust absorption in NGC 300. We argue that our current distance result for NGC 300 is the most accurate that has so far been obtained using Cepheid variables and that it is largely free from systematic effects due to metallicity, blending, and sample selection. It agrees very well with the recent distance determination from the tip of the red giant branch method obtained from HST data by Butler and coworkers, and it is consistent with the Cepheid distance to NGC 300 that was derived by Freedman and coworkers from CCD photometry of a smaller sample of stars.
  • No Thumbnail Available
    Item
    The optical afterglow of the gamma-ray burst GRB 012111
    (2002) Holland, ST; Soszynski, I; Gladders, MD; Barrientos, LF; Berlind, P; Bersier, D; Garnavich, PM; Jha, S; Stanek, KZ
    We present early-time optical photometry and spectroscopy of the optical afterglow of the gamma-ray burst GRB 011211. The spectrum of the optical afterglow contains several narrow metal lines that are consistent with the burst's occurring at a redshift of 2.14 +/- 0.001. The optical afterglow decays as a power law with a slope of alpha = 0.83 +/- 0.04 for the first approximate to2 days after the burst, at which time there is evidence of a break. The slope after the break is greater than or equal to 1.4. There is evidence of rapid variations in the R-band light approximately 0.5 days after the burst. These variations suggest that there are density fluctuations near the gamma-ray burst on spatial scales of approximately 40-125 AU. The magnitude of the break in the light curve, the spectral slope, and the rate of decay in the optical suggest that the burst expanded into an ambient medium that is homogeneous on large scales. We estimate that the local particle density is between approximately 0.1 and 10 cm(-3) and that the total gamma-ray energy in the burst was (1.2-1.9) x 10(50) ergs. This energy is smaller than, but consistent with, the "standard" value of (5 +/- 2) x 10(50) ergs. Comparing the observed color of the optical afterglow with predictions of the standard beaming model suggests that the rest-frame V-band extinction in the host galaxy is less than or similar to0.03 mag.