TMT and Time Domain Science

G.C. AnupamaIndian Institute of Astrophysics

TMT Science and Instrumentation Workshop. 2014 November 5-6, ARIES

VARIABILITY TREE

Time Domain Science

Transients– Gamma-Ray Burst Sources– Supernovae– Novae– LBV– Stellar Flares– Tidal Disruption Events– AGN flares– GW events

VariabilityStellar – orbital, rotation, pulsation,

accretion, evolution Galaxies – nuclear activity

Fig. Source: LSST Science Book

Class Mv (mag) T2 (days) LSST Rate (/yr)

LRNe -9 .. -13 20 .. 60 80 .. 3400

Fallback SNe -4 .. -21 0.5 .. 2 <800

Macronovae -13 .. -15 0.3 .. 3 120 .. 1200

Sne .Ia -15 .. -17 2 .. 5 1400 .. 8000

Sne Ia -17 .. -19.5 30 .. 70 200000

Sne II -15 .. -20 20 .. 300 100000

TDE -15 .. -19 30 .. 350 6000

Lum. Sne -19 .. -23 50 .. 400 20000

Orphan afterglows (SHB)

-14 .. -18 5 .. 15 10 - 100

Orphan afterglows (LSB)

-22 .. -26 2 .. 15 1000

On-axis GRB afterglows

.. -37 1 .. 15 ~50

Figs - Volume probed by various surveys as a function of transient magnitude. Red Cross: Minimum survey volume to detect single transient event.Lines for each survey – one transient event inthe specified cadence period.

Source: LSST Science Book

In the Era of Large Surveys, TMT is perfectly poised for time domain science

Courtesy, Josh Bloom, Berkeley

K~30 mag, 3σ in 3 hours – detections z>5

(WFOS-MOBIE, spectroscopic capabilities)

IRIS, Spectra, S/N ~ 10 (~ 1 hour)(Point source)J ~ 24.1H ~ 23.7K ~ 22.9

Seeing limited Imaging, S/N~100J ~ 27.3H ~ 26.2K ~ 25.5 (TMT_INS_TEC_10_001_REL02)

TMT capabilities for transients

TMT is optimized both in AO and seeing-limited modes for rapid response: ~5min without instrument change; ~10 min with instrument change

Study of TransientsAnd Variablity – A FewScience Cases in the TMT Detailed ScienceCases Document

(TMT-DSC-2014-draftV0.5.docx)Dated: 26 August 2014

11 Time-Domain Science

11.1 Overview

11.2 Understanding the Nature of Type Ia Supernovae

11.2.1 Characterizing high-z Type Ia Supernovae: Towards a Better Standard Candle

11.2.2 Unveiling Explosion Mechanism of Type Ia Supernovae

11.3 Identifying Shock Breakout of Core-Collapse Supernovae

11.4 Tracing high-z Universe with Supernovae

11.5 Hunt for Progenitor Systems of Supernovae

11.5.1 Detecting Progenitor and Companion of Supernovae

11.5.2 Characterizing Circumstellar environment around Supernovae

11.5.3 Probing the Final Stages of Massive Star Evolution: LBVs and Supernova Impostors

11.6 Identification of Gravitational-Wave Sources

11.7 Understanding Progenitors of Gamma-ray Bursts: Connection to Supernovae and

Kilonovae

11.8 Probing High-z Universe with Gamma-ray Bursts

11.9 Studying Tidal Disruption Events and Supermassive Black Holes

11.10 Cataclysmic Variables.

11.10.1 Investigating the Dissipative Process in Cataclysmic Variable Accretion Discs and Disc Evolution During Outburst Cycles.

11.10.2 Revealing Geometry and Populations of Classical Nova

11.11 Companions of Binary Radio Pulsars

11.12 Improving the Hubble Constant and Measuring Extragalactic Distances.

11.13 Time domain studies of AGN and Blazar Variability

11.14 Summary of Requirements.

11.15 References.

Supernovae

Thermonuclear SNe (Type Ia)Explosion of white dwarf in binary systems Energy - explosive C and O burning (fusion of C & O to Ni) - deflagration or detonationMaximum luminosity ~109 L_sun

Core-collapse SNeSpectrum: H (Type II); No hydrogen (Ib, Ic) Core collapse of massive stars (>8 M_sun) with large envelopes (still burning)Energy: gravityMaximum luminosity – 108 – 1010 L_sunPair Instability SNe

Z < 0.1 : KAIT, CfA, CSP, PTF; SKYMAPPER0.1 < Z < 1 : SNLS, Essence, SDSS; DES, PANSTARRS, GAIA, LSSTZ > 1 : HST-GOODS, WFC3; JWST, TMT, E-ELT, WFIRST

Type Ia Supernovae

Single degenerate – accreting WDs – possible progenitors: supersoft X-ray sources, recurrent novae, symbiotic novae

Double degenerate – WD merger

Early observations may allow us to test whether SNe Ia arise from single degenerate, double degenerate or sub-Chandra scenarios

Super Chandra SN Ia show unburned carbon in their outer layers, visible only at early times, but also seen in other lower luminosity Ia

High Velocity Ca II and Si II at early times detected in some SNe – related to shells or disks or progenitor material causing over densities in SN spectra

Evidence of circumstellar material – narrow hydrogen emission, absorption features, light echoes

Type Ia PTF11kx – Symbiotic RNe Progenitor?

PTF 11kx – z=0.04660 (Dilday et al. 2012)

High resolution Keck spectra (R~48,000) (-1d, +9d, +20d, +44d)Narrow CaII H&K features blue shifted by ~100 km/s (early spectrum) – develop into emissionNarrow absorption lines of NaI, FeII, TiII and HeI. Blue shifted at ~65 km/s. Na I lines increase in depth over time.Hydrogen Balmer series seen in absorption blue shifted at ~65 km/s. H-alpha and H-beta show P-Cygni profiles.Absorption systems very similar to that seen in the recurrent nova RS Oph that has a red giant secondary (Patat+ 2011)First evidence for the presence of a red giant secondary

TMT should be able to detect such systems in SNe Ia z~0.1 with good S/N

Type Ia SD Progenitors – Early Light Curve

Early Photometric Observations should reveal signatures of collision of supernova with its companion (Kasen 2010)

Luminosity due to collision is prominent at times t<8 days, for viewing angles looking down on the collision region for SN having collided with a red giant.

Dominant in X-ray, but R-J tail seen in UV/optical. Bump in B-band at t<5 days due to interaction with RG companion

Detection in high redshift SN Ia with the TMT (UV shifted to optical + time dilation)

Core Collapse Supernovae• Study of the shock break-out phase – IIP shock breakout in optical bands

(Tominaga et al. 2011 – theoretical light curves for range of progenitor masses)

• Early phase – typing, sub classes, peculiarities (follow-up important – change in types), pre-explosion dust and its composition

• Late phase (nebular) observations• Evolution of line profile and kinematic studies; explosion geometry

(Spectropolarimetry useful tool)• SNe IIP as standard candles – correlation of Fe II velocities with I band

luminosity – extend beyond the existing correlation upto z~0.3 • Study of type-IIn SNe (luminous) at z~6

– Normal IIn SNe – z~2– Strength and duration of the prominent emission lines present spectroscopic

detection of 2<z<6 IIn SNe for ~3-15 years after outburst • Luminous / Pair Instability SNe – The most massive, metal poor stars (metal

poor pockets in the nearby universe)• Progenitors – star formation history and IMF, metallicity – host galaxy local

environment / integrated

• GRB are brief, sudden, intense flash of gamma-ray radiation

• Prompt and afterglow emission,• Cosmological (z ~ 0.1 to 8.3),• Very Energetic (1050 to 1055 ergs),• Short, long Bi-modality in duration

• Supernovae Connections – long bursts Associated SNe – Ic hypernovae Are all LBGRBs associated with SNe? Is there a heterogeneity in the SN type?

• Dark GRBs• Orphan GRBs

Polarimetry – geometry, jets, circumburst mediumLate phase observations of GRB afterglows - Spectroscopy

• Host Galaxy – morphology, location of the GRB in the host galaxy, possible progenitors

Gamma Ray Bursts (GRBs)

Stellar Tidal Disruption Events

Strong transient outbursts from galactic nuclei – star, planet or gas cloud tidally disrupted and partially accreted by the central non-active SMBH

Transient variability may also arise during inspiral and merger phases of binary SMBHs

Flashes in X-rays and UV.

Optical flare, lasting several months expected when star disintegrates outside the event horizon

Two optical events detected in SDSS survey data. One by Panstarrs.

Stellar Tidal Disruption Events Optical Flares

Panstarrs TDE – PS1-10jh (Gezari+ 2012) – Discovery 2010 May 31z: 0.1696; mg 19.8 (peak)MBH ~ 2 106 M_sun (Mr-MBH correlation)Spectrum – Broad, high ionization He II lines – interpreted as the disruption of a helium star.Guillochan+ (2013) – suggest TDE produces a temporary accretion disc analogous to accretion disc in a normal thermal AGN, and that broad He II from a temporary BLR. Gaskell & Rojas Lobos (2013) – smoothed spectrum – H-alpha also present. - consistent with Guillochan et al.

Stellar Tidal Disruption Events Optical Flares

SDSS TDE (van Velzen+ 2011)z: 0.136, 0.251; Mg -18.3, -20.4MBH ~ 6-20 106 M_sun, 2-10 107 M_sun (Mr-MBH correlation)Spectrum – H-alpha emission in TDE2 few days after detection of flare

Interest in Stellar TDE

Light emitted after disruption sensitive to black-hole mass and spin – large samples of TDE will allow properties of SMBHs to be studied without relying on scaling relations with global properties of galaxies

TDEs are the only probes to obtain large samples of dormant SMBHs

Testing existence of IMBHs in Globular Clusters and dwarf galaxies

Detailed observations of emission from large sample of TDEs – new area for testing/understanding of accretion physics, constrain properties of disrupted stars

Follow-up of Gravitational Wave SourcesAccelerating Massive Objects in Asymmetric System Generates GW. Possible Sources - NS-NS(BH) collision (candidate of short GRBs); Core-collapse ofMassive starsLight Curves and spectroscopy - identification

LIGO(USA)

IndIGO(LIGO-India)

KAGRA (Japan)

Future: LISA, DECIGO (in space)

GW detection~ 100 deg2Localization

Search withSubaru/LSST/ZTF

Spectroscopywith TMT

Identification of GW sources

Cataclysmic Variables

Interacting Binary stars – Accreting white dwarf primary with a main-sequence M star secondary.

Nova Systems - Outburst due to thermonuclear runaway in the accreted hydrogen-rich material.

Outbursts can reach Mv = -10 – among the brightest transient sources known. Outburst intervals of decades (recurrent novae) to thousands (classical novae) years Outburst most sensitive to the mass of the accreting WD

Dwarf Nova systems - Outbursts occur due to disc instabilities, with the periodicity and amplitudes dependent on the accretion rate. At the highest accretion rates, there is no outburst (novalikes).

Between nova outbursts, the systems exist as dwarf novae or novalikes.

White Dwarf

Accretion Disc

Cataclysmic Variables: Some Open Questions

Sources of rapid variabilityVariety of observed wavelength/amplitude dependencies

Novae eruption mechanismsSuper-Eddington eruptions

Pulsating white dwarf properties and excitation mechanismsSource of negative superhumps in AM CVn systemsDwarf Nova OutburstsDisc Instability and Mass Transfer Instability outburst models

DNO and QPO models

Orbital angular momentum loss and the period gapCV formation and evolution in the field and Globular Clusters

White Dwarf mass evolution, AM CVn and SN1a progenitors

Dwarf Novae – Disc Instability

SS CygFlare lasting 2½ minutesFireball from the disc

Broad band photometry combined with Time-resolved spectroscopy can provideInformation regarding various disc activities, Spatial distribution of the instabilities (seen asFlickering), etc.

Geometry and Populations of NovaeNova Cyg 1992

Recurrent nova T Pyxidis

Nova GK Per 1901

The shape and ejected material kinematics of a nova shell : The shell burning process Collimation effects and environment immediately around the progenitor Non-spherical ejection – important consequences for understanding the observed propertiesInteractions with shell and circumstellar environment

Example: TMT + AO: For a nova at 5kpc which is ejecting mass at 1000 km/s As seen from the Earth, the ejected shell will have a size of 10 mas (0.01") in around 87 days. For a very fast nova, the time taken would be around 9 days. Coronographic spot required to mask the central star.

GK Persei 1901

He Nova V445 Pup

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Nova Populations

The high luminosity and frequency of appearance make novae ideal for probing properties of close binary systems in extragalactic (different) stellar populations

Novae have been observed in more than a dozen galaxies, some as distant as the Coma cluster.

Extragalactic novae also follow the MMRD relation (distance estimators) – presence of faint, fast CNe in M31 (Kasliwal+ 2011)

Are there two distinct populations of novae – do they depend on the Hubble type?

Are some recurrent novae progenitirs of Type Ia supernovae?

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Study of Compact Objects (Including Massive Black Holes)

Neutron Stars Companions of radio binary pulsars Magnetars AGN Activity

Long term Variability Intra-night Variability Flares

Summary

Time Domain Science is vast and varied

Transients – ToO, time resolved, time critical (and non-time dependent)

Variability studies - Time resolved science, time critical

Discussed a few possible science cases related to Transients

Time Domain ISDT

Conveners: G.C. Anupama, Masaomi TanakaMembers: Manjari Bagchi, Varun Bhalerao, U.S. Kamath, Lucas Macri, Keiichi Maeda, Shashi Pandey, Enrico Ramirez-Ruiz, Warren Skidmore, Nozomu Tominaga, Lingzhi Wang, Xiaofeng Wang, Chao Wu, Xufeng Wu

Invite participation in the Time Domain ISDT