The dynamical sky Two frontiers Joel Johansson, Uppsala university

Transcription

1 The dynamical sky Two frontiers Joel Johansson, Uppsala university Time Wavelength

2 Optical surveys faster! HSC, 1.7 deg 2 DES, 2.5 deg 2 PS1, 7 deg 2 PTF/iPTF, 7.3 deg 2 ZTF, 47 deg 2 LSST, 9.6 deg 2 Survey start: one year from nowtelescope! 1 deg

3 Optical phase-space of Transients

4 The dynamical sky GO FASTER! Fast transients (e.g. orphan GRBs, Cenko+15) Probe very final stages of stars lives! Companion star in Type Ia supernovae? (e.g. Kasen 2010) Shock break-out in core-collapse SNe (e.g. Rubin+2015) Flash -ionization of circumstellar material (e.g. Gal-Yam+2014) Apparent AB Magnitude Keck1 LRIS NOT ALFOSC FTS FLOYDS NOT ALFOSC P200 DBSP Hours from explosion PTF R-band 3σ limits Polynomial Fit Days from explosion (MJD ) Absolute Magnitude iptf13dqy (Yaron+17) First detection ~3 hours after explosion! First spectrum 3 hours after detection

5 Rapid ( Flash ) spectroscopy O VI He II O V (iptf13dqy, Yaron+17) Scaled F λ + shift (erg cm -2 s -1 Ang -1 ) O IV N V H KeckI NOT NOT P200 KeckII KeckII FTS +6.2 hr +7.2 hr +8.9 hr hr hr +1.4 d +1.9 d +2.0 d +2.1 d +5.1 d +5.3 d Rest Wavelength (Angstrom) FTS Dense CSM within ~10 15 cm Ejected during the final year at high rate (~10-3 M /yr)

6 Rapid ( Flash ) spectroscopy C III? N IV? (Johansson in prep.) Sample of ~20 PTF SNe (+ few objects from literature) with flashspectroscopy PTF has total of ~700 Type II supernovae. Still, not rare! ~14% of SNe II should show flash-features (Khazov+15)

7 The dynamical sky Two frontiers Time Wavelength

8 The dynamical sky GO REDDER! The Spitzer InfraRed Intensive Transients Survey (SPIRITS) metre mirror FOV - IRAC, post-cryo: 3.6 and 4.5 µm nearby galaxies (< 20 Mpc )

9 The dynamical sky GO REDDER! NGC 2403 (Credit: Howard Bond)

10 Mid-IR Phase-space of Transients 3.6um Mid-IR Luminosity (Abs Mag) Supernovae dust-dominated (V1668 Cyg) Novae metal-dominated (QU Vul) Type IIb (SN2011dh) Type Ia (SN2014J) Intermediate Luminosity Red Transients ~150 transients: 40 supernovae 20 novae 60 mysteries Time (Days)

11 Mid-IR Phase-space of Transients ~150 transients: 40 supernovae 20 novae 60 mysteries Extreme? >1200 variables Absolute Magnitude (3.6um) RSG O-AGB C-AGB Days

12 Mid-IR Phase-space of Transients 3.6um Mid-IR Luminosity (Abs Mag) Supernovae dust-dominated (V1668 Cyg) Novae metal-dominated (QU Vul) Type IIb (SN2011dh) Type Ia (SN2014J) Intermediate Luminosity Red Transients 14aei 14axa 14aje 14ajc Kasliwal et al. (in prep.) ~150 transients: 40 supernovae 20 novae 60 mysteries Mysteries = SPRITES No optical/nir counterparts! (Kasliwal+2017) Massive binaries driving shocks in molecular clous? Stellar mergers with dusty winds? Enshrouded SNe? Time (Days)

13 Mid-IR Phase-space of SUPERNOVAE Type IIn/Ia-CSM Core-collapse SNe Type Ia SNe Impostors Type IIn/Ia-CSM SNe e.g. Fox&Filippenko (2013) Core-collapse SNe Sample in Tinyanont+16 SN 2011dh (Helou+13) SN 2013ej (Mauerhan+17) SN 2014C (Tinyanont et al.) SN 2014bi (Johansson et al.) Type Ia SNe Sample in Johansson+17 SN 2014J SN Impostors SNHunt248 (Mauerhan+17)

14 The IR surprise from SN 2014dt Type IIn/Ia-CSM Core-collapse SNe - Peculiar, subluminous SN Iax - Nearby 12 Mpc) - Bright in the mid-ir! - Late time IR-rise (>2 4.5 μm)! SN 2014dt Type Ia SNe Impostors

15 The IR surprise from SN 2014dt ;c9bf5d Keck/LRIS, I-band, 5x240 sec. ( ) Mid-IR excess from warm dust? - M dust 10-5 M at T dust 700 K - Pre-existing or newly formed? (Fox, Johansson et al., 2016) - No progenitor in archival HST-images - No signs of reddening/na ID absorption (Foley et al. 2014, 2016)

16 The IR surprise from SN 2014dt SN 2014dt SN 2012Z Progenitor system in HST images. Luminous/blue Helium star, donor to accreting White Dwarf (McCully+14) Thermonuclear deflagration of a WD that doesn t completely unbind the star. (Kromer+13,15)

17 The IR surprise from SN 2014dt 1. Circumstellar dust? (no reddening / Na ID absorption ) 2. IR-catastrophe? (Fransson&Jerkstrand 2015) 3. Bound remnant? Optically thick wind blown from partially disrupted progenitor WD?

18 SUMMARY Pushing the time frontier allow us to find SNe as they happen (ZTF now on sky!) UV follow-up and flash-spectroscopy probes mass loss during the final year of stars lives (more robotic spectrographs coming up ) SPIRITS survey finding lots of previously missed transients! IR probes mass loss histories thousands of years prior to SN explosions