1. The LOFAR Transients Key Project
C\asey Law (Amsterdam)
"Quiquid differat notandum"
introduce self motivation of the project is to study the changing sky. things that change are interesting.  if that is not convincing, i can say it in latin.

2. Why now?  New technology!
what kind of technology?

3. Why now?  New technology!
very advanced, no? (no sheep were harmed in the making of this presentation)

4. Why now?  New technology!
more specifically, improved:  - data rate  - computation  - storage

5. Why now?  New technology!
e.g., in the past, bandwidth from telescope was limited by data rate and calibration complexity. now, we can move more and calibrate more. as yashwant gupta mentioned, phasing array is tough and must be active.  processing loop all 'on-line' on bg/p. we used to design the h/w to simplify analysis.  now s/w can take the complexities of a simple dipole.

6. With new techniques, come new capabilities
Pushing the boundaries...
Frequencies from 30 to 240 MHz
32 MHz BW can be processed
FOV = deg
8+ beams
these changes have given us access to new regions of telescope function.  - low freq  - wide bw (and large relative bw)  - large fov (and ok res'n)  - beams! Note that for timing purposes this is nice, but for an imaging interferometer, this is radical! new challenges:   - delta f/f makes bw smearing  - fov makes projection necess. Resolution (full) " - 3.5" Resolution (core) ' - 2.5' Sens (full, 1s) mJy

7. How will the TKP use LOFAR? The Radio Sky Monitor
Imaging survey at 30, 120 MHz
1 sec sensitivity:  500, 50 mJy
Covers 1/4 of sky daily
the new capabilities are best demonstrated in the RSM mode. this is a focus of much of our effort at the moment. rsm uses lofar core of ~18 stations.  lower resolution, but potentially more beams. designed to optimize survey figure of merit and find new physics: M ~ A * Omega * T/dt * Aeff/Tsys

8. Analysis for Radio Sky Monitor Image int'n times: 1s, 2s, 5s, ...
Real-time pipeline in Python
Events made public rapidly
Public access to database
Image
srcdet
alert
class db
logarithmic set of integration times analyzed => sensitive to short and long changes. e.g., 500mJy in 1s => lorimer burst, flare star 5 mJy in 10000s => xrb flare 2 image cubes/s/DM! must be fast and robust pipeline takes images, extract sources, databases, classifies, and alerts as necessary. more data than we can handle => public access archive searches should be fruitful.  includes monitoring sources.

9. Expectations for RSM Survey
       
Class                        Timescale                    Rate         GRB afterglows        minutes - months        ~100/yr
        Radio supernovae    days - months              ~5/yr         Flare stars                msec - hours                     Exoplanets               min - hours                          "Lorimer-like"            msec                               ?
range of distances from local to cosmological.

10. What kind of physics can we study
What kind of physics can we study? 1) Synchrotron emission: relativistic electrons in magnetic fields Seen in AGN, XRB, GRB, SNe. Open Questions:   - How are jets formed and collimated?   - How is accretion power carried away?
open questions are answered phenomenologically, e.g., recent "fundamental plane" of jet sources working group in tkp on "jet sources"

11. What kind of physics can we study
What kind of physics can we study? 2) Coherent emission: bulk motion of charged particles Seen in neutron stars, flare stars, GRBs. Open Questions:   - Is there prompt GRB emission?   - Do flare stars emit coherently and how?
Tb > 10^12 K

12. What kind of physics can we study
What kind of physics can we study? 3) Properties of the ISM/IGM: dispersion imprint information Open Questions:   - Can we improve on NE2001?   - Is the IGM like the ISM? 4) Discovery!  - Exoplanets  - GRB prompt emission  - Pulsar GPs  - ?
studying dm on >s timescales may give new vantage, different biases rsm would not detect lorimer burst, but perhaps with shorter integrations. crab-like gps would be easy with 1s integrations.

13. Challenges Calibration:  Will all sources seem "transient" from ionospheric effects? RFI:  Interference may mimic celestial transients. Data volume:  How long can we hold results of TKP pipeline?  Can we handle generic public queries? Latency:  Can system calibrate fast enough to allow responses to 1s-type events?
snapshot of current concerns

14. Summary
Next-gen interferometers are opening new possibilities in imaging surveys.
LOFAR will utilize this with the Radio Sky Monitor.
Data processed in real time and results made accessible.
Probing new regimes in time-domain astronomy promises exciting new results.

17. 2) Targeted Observations Full array observations
XRBs, Exoplanets, GRB/SN
Respond with Transient Buffer Boards or "natural buffer boards" -> dispersion delay
range of distances from local to cosmological. a streamlined system gives us a more uniform sensitivity.  => can estimate rates possible expansion ideas:  - add discussion of lofar trant survey