The Transient Universe: AY 250 Spring 2007 Existing Transient Surveys: Optical II: Robot Telescopes Geoff Bower

The Transient Universe: AY 250 Spring 2007 Contemporaneous Optical Burst with Gamma-Ray Burst GRB Akerlof et al 1999

The Transient Universe: AY 250 Spring 2007

Contemporaneous Optical Burst GRB –Fluence 99.6 percentile in gamma- rays Z=1.6 5 x 10^49 erg s^-1 at t=47 s –Most luminous optical event ever Many similar events predicted Burst trigger +4 seconds --- message with position arrives in LANL +10 seconds --- first observation begins (but software error fails) +22 seconds --- first good integration

The Transient Universe: AY 250 Spring 2007 ROTSE-I 4 x 35mm cameras with 2k x 2k CCDs 16 x 16 deg^2 FOV 14” pixels 3 sec slew time to anywhere on the sky Limiting magnitude of 15 Robotic operations LANL Based on military goals of Strategic Defense Initiative to track missiles $200k

The Transient Universe: AY 250 Spring 2007 ROTSE-III 4 stations –GRB follow-up at any time 4 x 0.45m aperture 16 x 16 deg^2 FOV 18 mag limit Designed to fit in a shipping container

The Transient Universe: AY 250 Spring 2007 Other GRB Follow-Up with ROTSE No detections Optical emission not strongly correlated with gamma-ray emission Akerlof 2000

The Transient Universe: AY 250 Spring 2007 GRB Li et al 2003 RAPTOR KAIT 105s179s 259s 9600s Many optically “dark” bursts have been missed by late observations

The Transient Universe: AY 250 Spring 2007 Swift UVOT observations of GRB Swift-diamonds

The Transient Universe: AY 250 Spring 2007 A Handful of Early Detections Jelinek et al 2006

The Transient Universe: AY 250 Spring 2007 Vestrand 2006

The Transient Universe: AY 250 Spring 2007 Wide & Narrow Views Vestrand 2006

The Transient Universe: AY 250 Spring 2007 Stereoscopic Vision 38 km separation Parallax of 1 pixel at distance of Moon Rejects space junk, satellites, aircraft, meteors Reduces false triggers by orders of magnitude

The Transient Universe: AY 250 Spring 2007 Vestrand 2006

The Transient Universe: AY 250 Spring 2007

ROTSE-III Search for Untriggered Bursts No New Transient Classes 1.74 deg^2 yr Brighter than 17.5 mag for 30 minutes 52 deg^2 yr Slowly decaying transients such as CVs 4 CVs discovered  0.1 deg^-2 yr- 1 Rykoff et al 2005

The Transient Universe: AY 250 Spring 2007 ROTSE-III Transient Light curve recalls classical nova –Abs. mag = -8 –  D=1 Mpc –But no host galaxy Dwarf nova –Subgroup of CVs –Resembles SU Uma- type DNe Rau et al 2006

The Transient Universe: AY 250 Spring 2007 Northern Sky Variability Survey ROTSE-I all sky data 14 million objects 1 year observations/object 8 < mag < 15.5

The Transient Universe: AY 250 Spring 2007 Finding Variable Stars in NSVS 2000 deg^2 10 < m < new periodic variables 90% are newly identified 0.2% of all stars variable above 0.1m 5% of total NSVS Akerlof et al 2000

The Transient Universe: AY 250 Spring 2007 Many Variable Types Automatically Identified RR Lyrae ABRR Lyrae C Delta Scuti Eclipsing

The Transient Universe: AY 250 Spring 2007 Use of Periodic Stars as Galactic Distance Indicators RR Lyrae detected from 0.7 to 7 kpc Tight period-luminosity relationship Periods less than 1 day Delta Scuti stars Periods less than 1 day Less luminous

The Transient Universe: AY 250 Spring 2007 Machine learning identifications Working on LPVs –AGB stars undergoing pulsations –Mira (M) Longer periods –Semiregular (SR) Periods < 1 y –Irregular (L) Data available –Period –Amplitude –3 colors Use training method for separating variables

The Transient Universe: AY 250 Spring 2007 Long Period Variables Wozniak et al 2004

The Transient Universe: AY 250 Spring 2007 Training Set Mira LPV

The Transient Universe: AY 250 Spring 2007 Classified Stars

The Transient Universe: AY 250 Spring 2007 Confusion Matrix 90% of training data used to construct basis 10% of training data used to estimate confusion  Classification accuracy 87%

The Transient Universe: AY 250 Spring Class Identification Training Set Mira LPV Carbon

The Transient Universe: AY 250 Spring 2007 Actual Classification

The Transient Universe: AY 250 Spring 2007 Confusion Matrix

The Transient Universe: AY 250 Spring 2007 Support Vector Machine Transform data into higher dimensional space Identify hyper-planes that create class boundaries Maximize the margin –Orthogonal distance between class boundary and points closest to the boundary

The Transient Universe: AY 250 Spring 2007 Summary Robot telescopes for rapid follow-up Robot telescopes for surveys Machine learning, automatic classification is critical