1. Searching for Transients with LOFAR/CS1 Casey Law (Amsterdam)

2. You know LOFAR... What is CS1? Possible layout of LOFAR stations Low-band antenna in CS1 Core Station 1 is a prototype LOFAR station Located in LOFAR core 96 LBAs and HBAs

3. Good for commissioning, good for science! Early LBA observations: Frequencies from 10 - 90 MHz Resolutions from 2 - 0.2 deg Bandwidth ~ 4 MHz Correlating 16 dipoles A eff ~ 128 m 2 dipoles have all-sky sensitivity...... produce all- sky maps

4. Ultimate goal: The Radio Sky Monitor Imaging survey at 30, 120 MHz 1 sec sensitivity: 500, 50 mJy Covers 1/4 of sky daily The RSM in action Sky coverage of the RSM

5. What will this produce? Image ~300 deg 2 /s Studies sky on range of timescales Lightcurves of all sources Public access to database

6. Image srcdet db class alert Transient Detection Pipeline (Posters by J. Swinbank and B. Scheers) Real-time pipeline in Python Starts with image cubes, produces source lists, alerts.

7. The Search Data: LBA, near 45 MHz Bandwidth = 4 MHz 24 hours Method: Image for times of 4, 8 min,..., 4, 8 hrs Area of ~1200 deg 2 Run source detection Search for good candidates Image of North Celestial Pole at 45 MHz. All 3C sources visible, some SNRs, M82. Search area shown in green.

8. Example lightcurves: 3C 390.3: 1 hour integrations 30 min integrations

9. Results For 10  threshold, no transients. Nondetection limits transient rate, f. For Poisson statistics, P(N det =0) = e -fN For 95% confidence, P(N det =0) = 0.05. Constraint on transinents in LOFAR CS1 survey.

10. Comparison to Previous Results STARE (Katz et al. 2003) MOTER (Amy et al. 1989 Green Bank 300ft (Gregory & Taylor 1986) FIRST/NVSS (Levinson et al. 2002) STARE Green Bank MOTER FIRST/NVSS

11. Summary 1.The TKP is actively developing tools to exploit LOFAR. 2.LOFAR/CS1 is able to do science today! 3.A 24 hour study of a 1200 deg^2 field found no transients. 4.Upper limits starting to constrain transient sky.