The Catalina Real-time The Catalina Real-time Transient Survey:Transient Survey:An Open Optical Transient Survey

Sept 19th, 2011Sept 19th, 2011

Andrew Drake, George Djorgovski, Ashish Mahabal,

Roy Williams, Matthew Graham, Ciro Donalek (Caltech),

Jose Prieto (Carnegie Obs), Marcio Catelan (PUC Chile),

Edward Beshore, Steve Larson (LPL)

Andrew Drake, George Djorgovski, Ashish Mahabal,

Roy Williams, Matthew Graham, Ciro Donalek (Caltech),

Jose Prieto (Carnegie Obs), Marcio Catelan (PUC Chile),

Edward Beshore, Steve Larson (LPL)

ajd@cacr.caltech.eduhttp://crts.calech.edu

The Catalina SurveysThe Catalina Surveys

•Catalina Real-time Transient Survey (CRTS) is a Caltech operated transient survey that started in Nov 2007 using from the Catalina Sky Survey (CSS).

•CSS is an NEO survey that began operation in March 2004.

• CSS operates three telescopes. Two in Tucson AZ & one in Siding Spring, Aus.

ObservationsObservations

• All CSS observations are taken unfiltered.• Observations 21 days/lunation.• Cover up 2000 sq. deg/night.

• With 4 images.• Mags ~19 – 21.

• Each telescope has an identical camera:

–Spectral Instruments camera with Imager Labs thinned 4K2 CCD.–14 second downloads

Catalina Sky Survey DiscoveriesCatalina Sky Survey Discoveries

Catalina Sky CoverageCatalina Sky Coverage

Total Catalina coverage 33,000 sq deg.

RA=0h

RA=12h

Catalina Transient SurveyCatalina Transient Survey The CRTS survey searches for highly varying astronomical The CRTS survey searches for highly varying astronomical

sources (sources (““optical transientsoptical transients””).).

Transients are found based on catalog comparisonsTransients are found based on catalog comparisons CSS coadds, USNO-B, PQ, SDSS.CSS coadds, USNO-B, PQ, SDSS. Remove artifacts and asteroids by detection coincidence and motion.Remove artifacts and asteroids by detection coincidence and motion.

All data is fully processed within minutes of observation.All data is fully processed within minutes of observation.

All discoveries are made public instantly to enable rapid follow-up.All discoveries are made public instantly to enable rapid follow-up.

Discover ~ 1 OT /10^6 measurements.Discover ~ 1 OT /10^6 measurements.

TransientsTransients

CRTS has discovered ~4000 transients.CRTS has discovered ~4000 transients. CSS 0.7m telescope, 4ys ~2100 OTs MLS 1.5m telescope, 2yrs ~1600 OTs SSS 0.5m telescope, 1yr ~300 OTs

CRTS transient discoveries include…CRTS transient discoveries include…

Main Transient TypesMain Transient TypesSupernovae ( > 800 discovered)2009+2010 twice number published by any other group(PTF, PanSTARRS, LOSS, etc.).

Cataclysmic Variables (> 500 discovered)More than any pastsurvey (eg. SDSS).

UV Ceti stars (flare stars)~100 discovered

Blazars>100 discoveredso far

100’s more transient sources100’s more transient sources

AGN-disk SN (CSS100217).AGN-disk SN (CSS100217).

Pair Instability SNe (SN 2009jh & SN 2007bi).Pair Instability SNe (SN 2009jh & SN 2007bi).

Young Stellar Objects (FU Ori, T Tauri)Young Stellar Objects (FU Ori, T Tauri)

High Proper Motion starsHigh Proper Motion stars

Classical Novae (CSS081007)Classical Novae (CSS081007)

Tidal disruption events (archival)Tidal disruption events (archival)

Extragalactic Luminous Blue VariablesExtragalactic Luminous Blue Variables

Variable stars (LPV, RR Lyrae)Variable stars (LPV, RR Lyrae)

Discovery LocationsDiscovery Locations

Red=SN, Blue = CV, Green=Blazar, Magenta=Other Galactic Coords.

SN red, CVs blue, blazars green, all others magenta.

Dwarf Nova type CVsDwarf Nova type CVsDwarf Nova type CVsDwarf Nova type CVsDelta mags up to 8.Rise time ~1-2 days.Repeat time days to decades.Possible transient fog for LSST.

Flare StarsFlare StarsFlare StarsFlare Stars

Flare of LHS-2397aFlare of LHS-2397aFlare of LHS-2397aFlare of LHS-2397a

1 2

3 4

Discovery NotificationDiscovery Notification

Three layers of event distribution.Three layers of event distribution.1) Real-time discovery (mins)

VOEvents, SkyAlert, iPhone

Automated Event DistributionAutomated Event Distribution

http://skyalert.org

Discovery data -> VOEvent xml. Notices published to SkyAlert.org, etc. Automated discovery agents create a portfolio from VO services (SIMBAD, NED, etc.) & catalogs (SDSS, NVSS, etc.)

Discovery NotificationDiscovery Notification

Three layers of event distribution.Three layers of event distribution.1) Real-time discovery (mins)1) Real-time discovery (mins)

VOEvents, VOEvents, SkyAlert

2) Human classified (mins-hrs)Event portfoliosHTML, iPhone, Circulars, Twitter

Classified EventsClassified Events

http://crts.caltech.edu

Evaluation of past information Including: light curves, images, colours, nearby sources (eg. x-ray, radio, galaxies) -> classification.Info on classification also published as VOEvents to SkyAlert.org.

Discovery NotificationDiscovery Notification

Three layers of event distribution.Three layers of event distribution.1) Real-time discovery (mins)1) Real-time discovery (mins)

VOEventsVOEvents

2) Human classified (mins-hrs)2) Human classified (mins-hrs)Event portfoliosEvent portfoliosHTML, iPhone, Circulars, TwitterHTML, iPhone, Circulars, Twitter

3) Events of interest (mins-days)Portfolios + follow-upATel, CBAT, VSNET

Extreme SupernovaeExtreme Supernovae

Extremely long timescale SNeExtremely long timescale SNe

Extremely bright SNeExtremely bright SNe

SN associated with very faint galaxiesSN associated with very faint galaxies

Long Lasting Supernova 2008iyLong Lasting Supernova 2008iy

Longest brightening Longest brightening supernova.supernova. Took ~400 days to brighten. Took ~400 days to brighten. ~20 times longer than a ~20 times longer than a

normal type Ia supernova.normal type Ia supernova. Type IIn SN.Type IIn SN.

Found in a galaxy ~500 Found in a galaxy ~500 times fainter than the Milky times fainter than the Milky Way.Way.

Catelan et al. 2009, CBET#1780

Host galaxy star

Long Lasting Supernova 2008iyLong Lasting Supernova 2008iy

Spectra of 2008iySpectra of 2008iy Black, Red P200 Cyan BTA 6m Green SMARTS

Long Lasting Supernova 2008iyLong Lasting Supernova 2008iy

Light curves of SN 2008iyLight curves of SN 2008iy

Shock breakout in SN2008iyShock breakout in SN2008iy

Normalized flux curves of 2008iy comp. to stretched Normalized flux curves of 2008iy comp. to stretched SN 2006gy and other SN.SN 2006gy and other SN.

O

O

4yrs later still going strong.4yrs later still going strong.

Keck spectrum of SN2008iy Keck spectrum of SN2008iy 1450 days after explosion! 1450 days after explosion!

Drake et al. 2011 in prep.

CSS100217CSS100217Luminous SN IIn, TDE, or AGN variability?Luminous SN IIn, TDE, or AGN variability?

• CSS light curve.CSS light curve.

CSS100217CSS100217

. SDSS NLS1 host galaxy spectrum. SDSS NLS1 host galaxy spectrum

CSS100217CSS100217• BPT emission diagramBPT emission diagram • NLS1 variabilityNLS1 variability

1500 SDSS NLS1 (Zhou et al. 2006)

CSS100217CSS100217

Follow-up spectraFollow-up spectra

CSS100217CSS100217• Event light curveEvent light curve

• Peak temp ~10^4K, Peak temp ~10^4K, weak radio, rapid varweak radio, rapid var

=> not TDE or AGN• SN IIn spectra SN IIn spectra (narrow +

evolving broad Balmer features) and SN light curve.and SN light curve.

Peak mag = -23 withPeak mag = -23 with

Ltot =1.3x10^52 ergLtot =1.3x10^52 erg

=> Most energetic and luminous SN known

Drake et al. ApJ 2011.

SN Host GalaxiesSN Host Galaxies

CRTS

Lick Obs Supernova Search (LOSS)

SN host galaxy mags.SN host galaxy mags.

Faint-galaxy Supernova SN 2008hpFaint-galaxy Supernova SN 2008hp Type Ia supernova Type Ia supernova Found in very faint Found in very faint

nearby galaxy.nearby galaxy. Redshift z=0.027Redshift z=0.027 Host Mr=-12.4,Host Mr=-12.4, ~7 mags ~7 mags

(~600x) fainter than the (~600x) fainter than the supernova itself.supernova itself.

Very few stars, so expect Very few stars, so expect few SNe.few SNe.

Host galaxy

SDSS image

Releasing the CSS datasetReleasing the CSS dataset

Six years of data from each telescope.Six years of data from each telescope. 1.5 million 4x4k images.1.5 million 4x4k images. History of 500 million discrete objects.History of 500 million discrete objects.cf. USNO-B 1 billion, SDSS dr7 ~400 million.

80 billion photometry points.80 billion photometry points.cf. USNO-B 3.6 billion, SDSS dr7 2 billion, COROT 290 million.

All CSS data is online &All CSS data is online & CRTS is making it all public.CRTS is making it all public.

Catalina Data ReleaseCatalina Data Release

During this workshop 1000 sq. deg.120 < RA < 240, 11 < Dec < 20:http://nesssi.cacr.caltech.edu/cgi-bin/getcssconedbvao.cgi

All CSS photometry will be released by November.

Transients SummaryTransients Summary~4000 unique optical transients:~4000 unique optical transients:>800 SNe.>800 SNe.>500 CVs.>500 CVs.>100 Blazars.>100 Blazars.>100 Flare stars.>100 Flare stars.~500 High amp vars, AGN, HPM stars, ~500 High amp vars, AGN, HPM stars,

etc.etc.

CRTS SummaryCRTS Summary CRTS has discovered ~4000 optical transients.CRTS has discovered ~4000 optical transients. All CRTS discoveries are made public All CRTS discoveries are made public

immediately (cf. PTF, PanSTARRS).immediately (cf. PTF, PanSTARRS). Discoveries include many extreme examples of Discoveries include many extreme examples of

supernovae.supernovae. During this workshop 1000 sq deg of photometry During this workshop 1000 sq deg of photometry

(120 < RA < 240, 11 < Dec < 20) is available at: (120 < RA < 240, 11 < Dec < 20) is available at: http://nesssi.cacr.caltech.edu/cgi-bin/getcssconedbvao.cgi

CRTS will make all CSS photometry public by CRTS will make all CSS photometry public by November.November.

http://crts.caltech.edu/CRTS is supported by NSF Grant No. AST-0909182

Fin.Fin.

Publications Publications

CRTS Circulars (> 1500)CRTS Circulars (> 1500) twitter.com/skyalert

Astronomer’s Telegrams (> Astronomer’s Telegrams (> 50)50)www.astronomerstelegram.org

CBETS (> 100) CBETS (> 100) www.cfa.harvard.edu/iau/cbet/RecentCBETs.html

VSNET Alerts (> 100)VSNET Alerts (> 100)www.kusastro.kyoto-u.ac.jp/vsnet/

• Journals (>25, mostly collaborative)Journals (>25, mostly collaborative)crts.caltech.edu/pub.html

Shock breakout in SN2008iyShock breakout in SN2008iy

Before During Breakout Difference

FU Ori Star CSS091110FU Ori Star CSS091110FU Ori Star CSS091110FU Ori Star CSS091110CSS lightcurve

HPM StarsHPM StarsHPM StarsHPM Stars

2005-06-03 2007-03-14

2008-03-10 2009-04-18

2MASS J14442067-2019222

CSS lightcurve

SummarySummary

CRTS has so far discovered …CRTS has so far discovered …

Automated Detection FilteringAutomated Detection Filtering

Detection coincidence filtering.Detection coincidence filtering. Image artifact filtering.Image artifact filtering. CSS coadd source comparison.CSS coadd source comparison. Remove known MPC asteroids.Remove known MPC asteroids. Motion filtering of new asteroids.Motion filtering of new asteroids. Discovery rate is ~ 1 OT /10^6 measurements.Discovery rate is ~ 1 OT /10^6 measurements.

Event follow-up Event follow-up

Supervised follow-up strategy: Supervised follow-up strategy: Photometry firstPhotometry first

P60, NMSU, DAO, HTN, CSS 1m (2011) (2011)

Spectroscopy only for transients appearing unusualSpectroscopy only for transients appearing unusual(avoid common SN like Ia(avoid common SN like Ia’’s based on colour normal luminosities) .s based on colour normal luminosities) .

Gemini N+S, Keck, P200, SMARTS, IGO, MDM.

External follow-up:External follow-up:

Foster follow-up of other transients by open publication Foster follow-up of other transients by open publication and collaboration.and collaboration.

ClassificationClassification

Review historical info.Review historical info. Broad light curve classes (CVs, SN, Vars, AGN).Broad light curve classes (CVs, SN, Vars, AGN). Comparison DSS, SDSS, PQ cats/images.Comparison DSS, SDSS, PQ cats/images. Datascope for: NED, SIMBAD, Downes, GCVS, Datascope for: NED, SIMBAD, Downes, GCVS,

FIRST, NVSS, 2MASS, ROSAT, Vernon, FIRST, NVSS, 2MASS, ROSAT, Vernon, CGRABS, etc.CGRABS, etc.

Combine elements to gain overall picture.Combine elements to gain overall picture.

Catalina Sky CoverageCatalina Sky Coverage

CSS Schmidt coverage ~23,000 sq deg

Long Lasting Supernova 2008iyLong Lasting Supernova 2008iy

Light curves of SN 2008iyLight curves of SN 2008iy LC of 2008iy comp. shifted & LC of 2008iy comp. shifted & stretched SN 2006gy.stretched SN 2006gy.