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

2. 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 were directly detected!); low-mass star
Remnant: neutron stars or black holes; complete disruption
Nizhnij Arkhyz, 2-8 July 2017

3. Introduction: Supernova Zoo
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4. Introduction: Supernova cartoonSN
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5. 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
Nizhnij Arkhyz, 2-8 July 2017

6. 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 also be detected!!!
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7. Observations: GRBs associated with SNe
SN2006aj / GRB/XRF monitoring
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8. Observations: GRBs associated with SNe
SN2008D/GRB/XRF monitoring
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9. 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
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10. Interpretation: hydrogen traces in SN2006aj spectra
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11. Interpretation: hydrogen traces in SN2006aj spectra
Sonbas, E.; Moskvitin, A. S.; Fatkhullin, T. A. et al., 2008
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12. 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 spectral resolution and signal-to-noise ratio
Nizhnij Arkhyz, 2-8 July 2017

13. Interpretation: search for hydrogen traces in SN2008D spectra
Moskvitin et al Branch et al.: late-time photospheric spectra may be affected by non-LTE effects (e.g. radioactive decay)
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14. Interpretation: comparison with „normal“ Type Ib supernovae
Within popular conception of Hypernova it was not generaly expected that our results should follow a relations obtained for «normal» SNe But our result shows that it is a high-speed tail of the «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)
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15. Interpretation: comparison with „normal“ Type Ib supernovae
Result for the hydrogen and helium
Back to the scientific background of the program … Do expansion velocities of GRB associated SNe differ from ones of «normal» events?
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16. 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
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17. Observations: GRBs associated with SNe, photometrical monitoring in world-wide collaboration
GRB B/SN2016jca: z = monitoring upto emergence of usualy faint host galaxy
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18. Observations: «normal» Type II-P SNe in collaboration with ARES group (India)
SYNOW models for Type II SNe, tracing evolution of expansion velocity for different ion shells (Roy et al., 2011)
SN2009bw bolometric lightcurve behavior showed one of the fastest recessions between the phases of the plateau and the nebular among the ever observed (Inserra et a;., 2012)
Nizhnij Arkhyz, 2-8 July 2017

19. Observations: «normal» Type Ib SNe
Type Ib SN 2012au:
Four month evolution CaII, FeII, HeI, SiII, HI, OI spectral lines SYNOW modeling of entire set of spectra
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20. Observations: luminous and superluminous Type Ic supernovae
Extremely luminous event, M< -21m, about an 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 ≤ Z☼) as a supernova progenitor
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21. 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 = based on host galaxy emission lines. The event absolute magnitude at the first observation MR = Monitoring showed a slow photometric evolution, < 0.5m for 4 month, but it is subject of futher multi-color observations
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22. Observations: superluminous MLS121104
The event was classified as Type Ic supernova. The redshift is measured from the host galaxy emission lines. The absolute magnitude at the brightness maximum is -21.3
Nizhnij Arkhyz, 2-8 July 2017

23. Observations: superluminous SN2009de
Redshift 0.319, MR = one of the most luminous event detected 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.
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24. 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
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25. 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 ) ~20% identified. Most of them are SNe type Ia (75%), ~5% - type Ib/c, rest - type II and pecular It is very important to identify events by spectroscopical methods!!! Thus we need 1 meter and larger class telescopes with efficient (throughput and spectral range coverage) 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
Nizhnij Arkhyz, 2-8 July 2017

26. Observational strategy: problems and prospectives
: 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
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27. Observational strategy: problems and prospectives
50cm-class robotic telescopes with field of view of ~ 100x100 arcminutes, multi-color CCD photometers The first two telescopes will start working in the middle of possibilities to detect supernovae at the early stage, search for specific type of events
«Right» strategy:
1) detection and multi-color photometric followup: small telescopes 2) spectroscopy: BTA and Zeiss ) late-time photometry: Zeiss-1000 and BTA
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28. Thank you!
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