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Monitoring Supernovae with SAO RAS 6-meter Telescope

This study focuses on the monitoring of supernovae using the 6-meter telescope at SAO RAS in Nizhnij Arkhyz from 2-8 July 2017. The observations aim to understand the properties and behavior of supernovae, including their luminosity, energy, progenitors, and remnants.

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Monitoring Supernovae with SAO RAS 6-meter Telescope

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  1. The monitoring of supernovae with the 6-meter telescope of SAO RAS T.A. Fatkhullin, A.S. Moskvitin et al.

  2. Nizhnij Arkhyz, 2-8 July 2017 Introduction: Supernovae • Transient events: unpredictable in time and space • Luminosity in brightness maximum: from -14m upto ~ -23m, ~4 order of magnitude • Kinetic energy of explosion >1050 ergs • Source of heavy elements in galaxies (especially, heavier than iron) • Powerful source of neutrino • Central engine: gravitation collapse of stellar core; thermonuclear explosion • Progenitors: massive stars, MMS≥ 8 M☼(recently it weredirectly detected!); low-mass star • Remnant: neutron stars or black holes; complete disruption

  3. Nizhnij Arkhyz, 2-8 July 2017 Introduction: Supernova Zoo

  4. Nizhnij Arkhyz, 2-8 July 2017 Introduction: Supernova cartoon SN

  5. Nizhnij Arkhyz, 2-8 July 2017 Background: GRB-SN connection • Still unresolved questions: «Do all long-duration GRBs are associated with SNe?», «Do such SNe differ from „normal“ events?» • Observations have demonstrated that in a statistically significant number of cases (30-40%) the expansion of the SN envelope may be asymmetric • From recent 3D core-collapse simulations to physics of GRB inner machine: assymetrical explosion as a generic feature (e.g. spiral modes of the standing acretion shock instability and bipolar lepton-emission self-sustained instability) • From GRB optical transients to core-collapse supernovae observations

  6. Nizhnij Arkhyz, 2-8 July 2017 Observations: GRBs associated with SNe 18 spectroscopically confirmed GRB-SN, + ~ 30 photometrical GRB-SN based on the bumps at lightcurves (Cano et al., 2016) «classic» SNe observations time region SNe features may alsobe detected!!!

  7. Nizhnij Arkhyz, 2-8 July 2017 Observations: GRBs associated with SNe SN2006aj / GRB/XRF060218 monitoring

  8. Nizhnij Arkhyz, 2-8 July 2017 Observations: GRBs associated with SNe SN2008D/GRB/XRF080109 monitoring

  9. Nizhnij Arkhyz, 2-8 July 2017 Interpretation: parametrical modelling of supernovae spectra • SYNOW code (Branch et al. 2001) • Basic model assumptions: • Spherical symmetry • Homologously expanding ejecta (v ~ r) • Black body radiation is emitted from a sharp photosphere • Two types of model P-Cyg profiles: undetach and detached cases

  10. Nizhnij Arkhyz, 2-8 July 2017 Interpretation: hydrogen traces in SN2006aj spectra

  11. Nizhnij Arkhyz, 2-8 July 2017 Interpretation: hydrogen traces in SN2006aj spectra Sonbas, E.; Moskvitin, A. S.; Fatkhullin, T. A. et al., 2008

  12. Nizhnij Arkhyz, 2-8 July 2017 Interpretation: search for hydrogen traces in SN2008D spectra More complicated case! There are no confident separation of CII and HI. There was no Hβ detection. One needs a higher spectralresolution and signal-to-noiseratio

  13. Nizhnij Arkhyz, 2-8 July 2017 Interpretation: search for hydrogen traces in SN2008D spectra Moskvitin et al. 2010Branch et al.: late-time photospheric spectramay be affected by non-LTE effects (e.g. radioactive decay)

  14. Nizhnij Arkhyz, 2-8 July 2017 Interpretation: comparison with „normal“ Type Ib supernovae Within popular conception ofHypernova it was not generalyexpected that our results should follow a relations obtained for «normal» SNeBut our result shows thatit is a high-speed tail ofthe «phase-velocity» relation Agreement of the photosphere (from Fe II ion) expansion velocities of SN 2006aj and SN 2008D with the empiric power-low velocity drop of classic CCSNe type Ib (Branch et al., 2002)

  15. Nizhnij Arkhyz, 2-8 July 2017 Interpretation: comparison with „normal“ Type Ib supernovae Result for the hydrogen and helium Back to the scientific background of the program …Do expansion velocities ofGRB associated SNe differfrom ones of «normal» events?

  16. Nizhnij Arkhyz, 2-8 July 2017 Observations: GRBs associated with SNe, photometrical monitoring in world-wide collaboration Z = 0.282,observed with NOT, MITSuME 50cm, Mondy, 10.4m GTC, TSAO, SAO RAS, etc.monitoring to detect and measure«bump» in GRB optical transient lightcurve

  17. Nizhnij Arkhyz, 2-8 July 2017 Observations: GRBs associated with SNe, photometrical monitoring in world-wide collaboration GRB 161219B/SN2016jca:z = 0.1475monitoring upto emergenceof usualy faint host galaxy

  18. Nizhnij Arkhyz, 2-8 July 2017 Observations: «normal» Type II-P SNe in collaboration with ARES group (India) SN2009bw bolometric lightcurve behaviorshowed one of the fastest recessions between the phases of the plateau and the nebular among the ever observed(Inserra et a;., 2012) SYNOW models for Type II SNe, tracing evolution of expansion velocityfor different ion shells (Roy et al., 2011)

  19. Nizhnij Arkhyz, 2-8 July 2017 Observations: «normal» Type Ib SNe • Type Ib SN 2012au: Four month evolutionCaII, FeII, HeI, SiII, HI, OI spectral linesSYNOW modeling ofentire set of spectra

  20. Nizhnij Arkhyz, 2-8 July 2017 Observations: luminous and superluminous Type Ic supernovae • Extremely luminous event, M< -21m,aboutan order higher in luminosity than ordinary events • May be detected from distant galaxies (already found at z~0.9) • Proposed models require very high masses of ejected matter Mej ~ 40M☼, M56Ni ~ 6M☼ and a high value for kinetic energy Ekin ~ 1052 erg • The most intriguing fact is that all models require also a very massive star Minit ~ 100 — 230M☼ (at the Main Sequence) of an extremely low metallicity (Z ≤ 0.001 Z☼) as a supernova progenitor

  21. Nizhnij Arkhyz, 2-8 July 2017 Observations: luminous AT2016enf event Luminous event AT2016enf was observed with 6-meter and Zeiss-1000 telescopes.It was identified as Type I supernova at redshift z = 0.291 based on host galaxy emission lines.The event absolute magnitude at the first observation MR = -20.3Monitoring showed a slow photometric evolution, < 0.5m for 4 month, but it is subject of futhermulti-color observations

  22. Nizhnij Arkhyz, 2-8 July 2017 Observations: superluminous MLS121104 The event was classified asType Ic supernova. The redshift is 0.303 measured from the hostgalaxy emission lines.The absolute magnitude atthe brightness maximum is-21.3

  23. Nizhnij Arkhyz, 2-8 July 2017 Observations: superluminous SN2009de Redshift 0.319, MR = - 21.9one of the most luminous eventdetected so far Observed with CSS 0.68-m Schmidt, Palomar 60,Hale telescope (Palomar 200), 6-m BTA, 1-m Zeiss-1000 (SAO RAS), Keck-I.

  24. Nizhnij Arkhyz, 2-8 July 2017 Observations: ultra-luminous SN2009de Spectra look like ones of broad-line (SN1998bw-like,a common property of GRB associated events), but some difference is also seen

  25. Nizhnij Arkhyz, 2-8 July 2017 Observational strategy: problems and prospectives Modern surveys (PT1, CRTS, ASAS-SN, ATLAS, Gaia, MASTER и др.) discover thousands of SNe candidates per year (~10000 during 2015-2016)~20% identified. Most of them are SNe type Ia (75%), ~5% - type Ib/c, rest - type II and pecularIt is very important to identify events by spectroscopical methods!!! Thus we need1 meter and larger class telescopes with efficient (throughput and spectral rangecoverage) spectrograph! Observation strategy is straitforward: • a list of potentially interesting objects is selected (info from surveys) • both spectra in a wide range of wavelengths and images are obtained • the spectra are reduced and compared with the SNID (SuperNovae IDentification) database (idealy, all should be done during the night) • type, age and approximate/precise redshift are determined

  26. Nizhnij Arkhyz, 2-8 July 2017 Observational strategy: problems and prospectives 2015-2016: total 16 new candidates were classified AT2016emb SN-candidate identification:the event is of Type Ic at redshift of 0.065 AT2016emj SN-candidate identification:the event is of Type Ia at redshift of 0.073

  27. Nizhnij Arkhyz, 2-8 July 2017 Observational strategy: problems and prospectives 50cm-class robotic telescopes with field of view of ~ 100x100 arcminutes,multi-color CCD photometersThe first two telescopes will start working inthe middle of 2018possibilities to detect supernovae at the early stage, search for specific type of events «Right» strategy: 1) detection and multi-color photometric followup: small telescopes2) spectroscopy: BTA and Zeiss-10003) late-time photometry: Zeiss-1000 and BTA

  28. Nizhnij Arkhyz, 2-8 July 2017 Thank you!

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