This is a special venue for me! 32

1

Time Domain Astronomy: The Next Decade S. R. Kulkarni Caltech Optical Observatories

MAJOR DIVISION: VARIABLE OBJECTS & TRANSIENTS 332

Variable Objects Key measurement: Light Curves – Photometric Precision Low: RR Lyrae, Cepheids, AGN, Type Ia Moderate: Eclipsing Binaries, Gravitational Lensing High: Planetary Transits, Asteroseismology What is of value? – Total number of visits usually matters more than cadence Spectroscopy (followup) – In most cases rapid follow up is not essential – In many cases spectroscopy helps but is not crucial 432

Transient Objects Imaging surveys provide the starting point for investigation – Supernova investigations are triggered by detection of a rising object – For many studies the follow up is decoupled from the initial detection of a GRB (at high energies) Cadence control is critical – On the first night of an imaging survey the detected transients are dominated by old supernovae – Conversely lack of cadence control presents significant opportunity costs (negative) Cadence directly determines the phase space that is being explored – “Universal” cadence simply means that everyone is equally unhappy 532

This Talk Focused entirely on transient object astronomy Main thesis: – Transient object astronomy is served best by sharply focused time domain surveys – Conversely, the returns from a generic time domain survey are likely to be quite poor (and wasteful of follow up resources) Transient Object Astronomy has a bright future in this decade and likely to continue into the next decade (when TMT will become operational) – However, TMT time is precious – Transient object astronomy has its own learning curve – The TMT collaboration must start preparing now 632

AN EXEMPLAR 732

The Intermediate Palomar Transient Facility (iPTF)

P48 P60 P The Palomar Observatory

P48 Discovery P60 Confirmation P200 Spectroscopy 3210

32 Kasliwal 2011 (PhDT) 11

12 Super-luminous Supernovae (no Hydrogen) 32

Death Omen! 3213 PTF10tel

Double degenerates: The new frontier 3214 Source: LISA Mission, NASA

ON TO LOW LATENCY (SAME NIGHT) 3215

3216

Progenitor of a Ib Supernova! 3217

What next? S. R. Kulkarni

Short timescale is terra incognito 32 19

PTF11agg: Dirty Fireball? 3220

Same night arcsecond localization of error region of 72 square degrees! 3221

As we go to press! GRB131011A M. Kasliwal L. Singer 2232

TITLE: GCN CIRCULAR NUMBER: SUBJECT: Fermi : iPTF detection of a possible optical afterglow DATE: 13/10/12 12:09:55 GMT FROM: Mansi M. Kasliwal at Caltech/Carnegie M. M. Kasliwal (Carnegie Observatories/Princeton), L. P. Singer (Caltech) and S. B. Cenko (NASA/GSFC) report on behalf of the intermediate Palomar Transient Factory (iPTF) collaboration: Starting :26 UT, we imaged about 70 deg^2 in the vicinity of the localization of the Fermi-GBM trigger with the Palomar 48-inch Oschin telescope (P48). Sifting through 10,816 candidate variable sources in the GBM error circle using standard iPTF vetting procedures including Palomar 60-inch follow-up, we identify iPTF13dsw as a possible optical afterglow RA(J2000) = 02h 10m 06.38s DEC(J2000) = -04d 24' 40.3" Light Curve: 05:26 UT (P48), 08:07 UT (P60) iPTF13dsw is 3.4 deg away from the center of the final GBM localization (68% statistical confidence radius of 2.75 deg). Nothing was detected at this location to a limiting magnitude of 20.6 mag on 2013 Sep 25. At 08:56 UT, we obtained a Gemini-South/GMOS spectrum in twilight. The spectrum is mostly featureless, with no prominent emission or absorption lines between A

WHAT IS THE METRIC OF SYNOPTIC SURVEYS? 2432

Proposed Metrics The “Reach” Etendue, AΔΩ Point source sensitivity, AΔΩ/θ 2 These metrics make sense only for static surveys. Not relevant for transient surveys For transients mere detection in itself is limited value Classification and follow up is the key 2532

Fundamental Parameters of a Time Domain Survey (Transients) Field-of-view (FOV), ΔΣ Sensitivity (6σ), S l Time to move one FOV, τ m Cadence: typical time separation between re- visit to the same FOV Basic Integration time, τ s (frame time) – Assume 60-s for all surveys 2632

Areal Rate Short Duration Transients (T<τ s ) Long Duration Transients (T>τ s ) If follow up is essential then all that matters is S l (set by follow up) and the parameters shown above. For 21- mag ZTF is 250 times faster than say HSC. 2732

Zwicky Transient Facility

47-sq degree camera for P

The SED Machine for P60 7 arcminute 30 arcsec PI: Nick Konidaris, PS: Robert Quimby In collaboration with NCU-Taiwan 3032

A Proposal: TMT Community based Transient Object Facilities Recognizing that transient object astronomy is a growing field with great promise the TMT community should ensure that it has access to quality transients Transient searches have three fundamental parameters and as such the idea that a single facility (equipped with “Universal Cadence”) can provide the transient stream is incorrect The preparation for this should start now so that the event streams will be ready by

ZTF Annual Workshops The ZTF consortium will be holding yearly meetings (along the lines of the very successful iPTF 2013 Workshop) – We plan to invite key players from TMT consortium to attend these meetings 32