X-ray Transient Surveys

Daryl HaggardGreg Sivakoff

Overview• X-ray photons assigned arrival time, energy, and sky position

– sensitive, energy-dependent light curves– time-resolved spectroscopy

• Baselines span – 10 orders of magnitude at spatial resolutions of arcseconds– 13 orders of magnitude at spatial resolutions of a degree

• High energy time domain data indicate variability in– AGN– Galactic center sources– X-ray binaries– Supernovae– Classical novae, recurrent novae– Magnetars– GRBs– Stellar flares– As-yet unknown X-ray variables

X-ray Missions

Planned/Proposed– NuSTAR– AstroSAT– eROSITA– GEMS– ASTRO-H – Athena– LOFT– WFXT– JANUS– EXIST

Active (+Archival)– Chandra– XMM– Swift– INTEGRAL– MAXI– Suzaku

Archival– RXTE– ROSAT

The Case for X-ray Transients

1. What are the most compelling science cases for current and future X-ray transient studies?

2. What efforts does the X-ray transient community need to undertake to best lobby for the importance of X-ray transient studies (past and present) to the general astronomical community?

Resource Utilization

1. How will new planned or soon to be launched instruments support X-ray transient surveys?

2. What inventive ways can we develop to utilize new instruments that may not be originally designed for X-ray transient studies?

3. What steps do we need to take to transition from the era of RXTE to the era without it?

4. What important lessons have we learned from RXTE?

Multiwavelength Coordination

1. How do we best coordinate multi-wavelength observations, especially for X-ray transient surveys?

2. Do we need to develop an X-ray Transient Network or are existing infrastructures like The Gamma-ray Circular Network and the Astronomers Telegram sufficient?

3. What cadences are needed to achieve various science priorities at different wavelengths?

4. Are there opportunities for citizen science with X-ray transient surveys?

Workshop Synopsis

Schematic of Variables/Transients

Eyer, et al. 2008Mahabal, this meeting

Tidal Disruptions

Variable Disks

Winds and Jets

Tidal Disruptions

Disks & Jets

SNe/GRB

Stellar Flares

Mergers/GRB

Mostly X-ray viewpoint

X-ray Time Domain Desirati

Discovery & Monitoring

• All Sky Monitor• MAXI/AstroSAT,

Lobster-eye technology, LOFT

• Science drivers: GRBs, SNe shock breakout, accretion physics, tidal disruptions

• ~Daily Cadence

Rapid Response• Rapid slew (< hr)• Swift, AstroSAT,

LOFT, a suite of Swifts!?

• Science drivers: GRBs, stellar flares/space weather, transient response

• High Availability

High Time Resolution

• Sub-ms timing• AstroSAT,

Athena,LOFT?

• Science drivers: Strong gravity, neutron star physics, XRB physics, QPOs

• High Sensitivity