Update on Jets WG activities

Sera Markoff
LOFAR Transients Key Project Meeting, Meudon, December 2011

Transcript

1. Jets WG S. markoff, J. Miller-Jones, R. Fender, R. Wijers, J. Broderick, J. Eislöffel, M. Hardcastle, R. Plotkin,V. Tudose (+ commissioning science folk)
2. Jet Science Jets are produced whenever there is accretion/collapse of magnetized plasma, combined with system rotation
3. Jets form in many astronomical objects GRS 1915+105 STELLAR-MASS BLACK HOLES SUPERMASSIVE BLACK HOLES Cygnus A DEAD STARS SS 433 R AQUARII CRAB PULSAR DYING STARS PN M2-9 Cas A GRB FORMING STARS HH 47 Text DISRUPTED STARS!
4. Jet Science Jets are produced whenever there is accretion/collapse of magnetized plasma, combined with system rotation Often relativistic, they carry significant energy from the central object and dump it well beyond its original gravitational reach: Kinetic energy, electromagnetic fields, high energy particles Impact can drastically effect surroundings: Heat/ionization, alter star formation, inflate bubbles, CRs generate turbulence/magnetic fields To understand, need better overall understanding of jet formation and internal physics (transient jets often provide more information). For BH/NS ➠ GR too!
5. Jet Science Jets are produced whenever there is accretion/collapse of magnetized plasma, combined with system rotation Often relativistic, they carry significant energy from the central object and dump it well beyond its original gravitational reach: Kinetic energy, electromagnetic fields, high energy particles Impact can drastically effect surroundings: Heat/ionization, alter star formation, inflate bubbles, CRs generate turbulence/magnetic fields To understand, need better overall understanding of jet formation and internal physics (transient jets often provide more information). For BH/NS ➠ GR too!
6. Types of objects Specifically, we have people/groups focused on: (Transient) jets in (transient/persistent) X-ray binaries GRBs YSOs? Not clear how transient they will be... AGN/blazar flares Objects we would also like to consider in the future: Tidally captured star events (Bloom et al. 2011) PWN? (Crab is showing flares, polarization) AGN Scintillation? Not exactly transient in “classical” definition but could be useful test
7. Main goals and challenges Training the automated transients pipeline to recognize various jets and decide the followup strategy Problem 1: many jet types look similar to each other (flat or steep spectrum, short scale variability) Problem 2: We don’t know much about how these objects behave/look (spectra/light curves) in Lofar bands yet, (James: VLSS, VLA 74 MHz + GMRT)
8. “Signature” emission of compact jets (“cores”) is flat/inverted synchrotron radiation ~ν-(p-1)/2 νbreak(B,ν,n,r) ~ν+5/2 FЗ З
9. FЗ З “Signature” emission of compact jets (“cores”) is flat/inverted synchrotron radiation
10. ?? Seen with LOFAR only if source is optically thin!
11. Main goals and challenges Training the automated transients pipeline to recognize various jets and decide the followup strategy Problem 1: many jet types look similar to each other (flat or steep spectrum, short scale variability Problem 2: We don’t know much about how these objects behave/look (spectra/light curves) in Lofar bands yet, (James: VLSS, VLA 74 MHz + GMRT) Multiwavelength data is critical, study several sources in several bands, use later to calibrate Lofar-only transient detections ➠ lots of overlap now with MW WG + commissioning/discovery WG’s What can be done in the meantime?
12. Recent activity Alexander’s talk: commissioning in progress, have images of several sources, but we are not yet at the point of extracting scientific parameters (spectra etc) easily Continuing to develop co-monitoring with TeV gamma- ray facilities, rather unexplored territory spanning the largest ν range, and include blazars as a study focus MoU’s with HESS (Stefan Wagner/Karl Kosack), MAGIC (Marc Ribo), VERITAS (John Quinn) for co-triggering Tried to establish connection with MOJAVE BLAZAR collaboration but not enough manpower on their side
13. Recent activity Alexander’s talk: commissioning in progress, have images of several sources, but we are not yet at the point of extracting scientific parameters (spectra etc) easily Continuing to develop co-monitoring with TeV gamma- ray facilities, rather unexplored territory spanning the largest ν range, and include blazars as a study focus MoU’s with HESS (Stefan Wagner/Karl Kosack), MAGIC (Marc Ribo), VERITAS (John Quinn) for co-triggering Tried to establish connection with MOJAVE BLAZAR collaboration but not enough manpower on their side
14. Tasks on ~6 months τ (Note: many of these on the table for awhile now, mainly in “wait and see” mode for commissioning fields) Training pipelines ➠ still need to make initial guess predictions to give to Evert (talk to VAST folk?) Decision trees post-detection pipeline: when/what to trigger? (need actual Lofar + MW data to be sure on this one) Define VOEvent field definitions of interest to the various jetted transient objects (a la John’s talk) Formulate our needs for coming proposal rounds (Class A/B) ➠ mix of analysing fields of known objects, monitoring of known/new transients (TOOs) or fields of interest Classification & Analysis
15. Good news / potential roadblocks On the positive side: we know a lot more about transient physics than we did 5 years ago, from MW campaigns Facing same issues as everyone else right now: (Alexander’s talk) Calibration/imaging still a challenge ➠ we are not yet at the stage where we know what any given source looks like at low frequency Lack of manpower ➠ please talk to me if you can help! Trying to attract a postdoc to focus only on blazar variability but... Inability to detect and/or analyze transients in real time, hopefully in next year along with MW working group (next talk) we can work towards being ready for the day it’s possible...