1 / 11

Searching for Transients with LOFAR/CS1

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

kami
Download Presentation

Searching for Transients with LOFAR/CS1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  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        Aeff ~ 128 m2 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 deg2/s • Studies sky on range of timescales • Lightcurves of all sources • Public access to database

  6. Image srcdet class db 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 deg2 • 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(Ndet=0) = e-fN For 95% confidence, P(Ndet=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) Green Bank FIRST/NVSS STARE MOTER

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

More Related