Andreas Horneffer

Status of MKSP LOFAR Observations

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Contents Where we are

Old observations Cycle-0 observations

Open Issues My list of Milestones

Cycle-0 and Cycle-1 Observations

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M51Early Image

M51 with 3C295 as calibrator Observed to test calibration interpolation and study M51

3C295 field M51 closeup

D. Mulcahy

M101

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M51Better Image

D. Mulcahy

After ca. 9 months of work

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NGC891

1 subband, basic calibration selfcal-bias source held for a real transient

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Fan Region

FD = -5 rad/m/m FD = -2 rad/m/m

M. Haverkorn, M. Iacobelli

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Double Double B1835+620

M. Orru

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Prediction of Ionospheric RM from GPS data

Comparison of Ionospheric RM prediction (red) and pulsar data (blue).

Ionospheric RM prediction can be included in BBS

C. Sobey and C. Sotomayor

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IC342

Cycle-0 regular observation data 1 Subband, basic calibration

C. van Eck

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Open Issues

List of Milestones: Normal Imaging1. Long integrations of polarization

Multi-hour observations2. RM Cubes with absolute FD

Multi-Epoch observations3. High Resolution in FD4. Low instrumental Polarization5. High angular resolution

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Milestone 0: Normal Imaging

Need to calibrate data: Station clocks Ionospheric delay Station gains (incl. dipole gains)

Selfcal needs good model of the sky to work Have a good sky model from e.g. MSSS Transfer solutions from a second beam on a calibrator. Be careful when using e.g. gsm.py skymodel!

Demixing, sagecal, BBS must not corrupt polarization information.

Still several Features missing in the software

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5ns Problem Solved

LOFAR had a major hardware issue last year “5 ns” issue

This has been solved with new hardware

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Milestone 1:Long Integrations

Needs Conversion between visibilities and Stokes parameters done correctly correct beam model -> test it with pulsar and all sky data

Needs the ability to correct for changes in the ionospheric RM calibrate on pulsars or with GPS based corrections -> GPS based corrections alone are not good enough.

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Ionospheric RM Correction

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Ionospheric RM Correction

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Milestone 2:RM Cubes with absolute FD

Needed for multi-epoch observations Needs at least one calibrator with known absolute

RM Get it from studies of measured RM and e.g.

ionospheric RM from GPS Connect the position angle of a source (a blazar?) to

higher frequencies. “Assign” a RM to a calibrator and use it as reference

Propagate absolute RM to all calibrators

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Milestone 3:High Resolution in FD

Needs wide frequency coverage -> 8-bite mode works! Multi-epoch observations for HBA low and high? Use the low-band?

Probably not…

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Milestone 4:Low Instrumental Polarization

Good understanding of the instrument For the time being: flag out parts at RM ≈ 0

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Milestone 5:High Angular Resolution

Needs us able to deal with long baselines. Made a start at the long-baseline BW Rely on the long baseline working group for the

time being.

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LOFAR Cycle 0 Regular Cycle 0 observations started December

2012 Originally planned till end of August 2013 Extended till 14. November 2013

(To implement and test the new correlator.) The nearby galaxies proposal got granted:

112 hours observing time 213 hours computing time

We asked for more time due to the extension

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LC0 Scheduling March - August

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MKSP Clycle-0:Nearby Galaxies

Target Band Observer Requested time Observed Date UTC Time LST RangeM31 HBA (110-190) Giessuebel 8h New Time 26. Sep. 2013 20:00 – 04:00

LBA (30-88) Giessuebel 8h New Time 27. Sep. 2013 20:00 – 04:00M33 HBA (110-190) Paladino 8h New Time 9. Oct. 2013 20:00 – 04:00

LBA (30-88) Paladino 8h New Time 10. Oct. 2013 20:00 – 04:00M51 HBA (110-190) Mulcahy 8 h 22. Apr. 2013 20:00 – 04:00 10:30 – 18:30M81/M82 HBA (110-190) Adebahr 5 h 6. Mar. 2013 21:26 – 02:30 08:52 – 14:00

5 h 30. Mar. 2013 19:00 – 00:20 08:00 – 13:21LBA (30-88) Adebahr 5 h 21. Feb. 2013 21:05 – 02:10 07:40 – 12:46

5 h 31. Mar. 2013 19:00 – 00:00 08:04 – 13:05NGC891 HBA (110-190) Mulcahy Cycle-1

LBA (30-88) Mulcahy Cycle-1NGC3079 HBA (110-190) Sotomayor 0 h ---- ---- ----

NGC4631 HBA (110-190) Sotomayor 8 h 9. Apr. 2013 18:00 – 02:00 07:40 – 15:41NGC6946 HBA (110-190) Jurusik 8 h 15. Jul. 2013 20:00 – 04:00 16:02 – 00:04IC342 HBA (110-190) Mulcahy / v.Eck, Pietka 5 h 2. Feb. 2013 15:50 – 20:50 01:09 – 06:10

5 h 13. Mar. 2013 22:20 – 04:00 10:14 – 15:55LBA (30-88) Mulcahy or Adebahr 5 h 30. Jan. 2013 16:00 – 21:00 01:07 – 06:08

5 h 21. Feb. 2013 16:00 – 21:00 02:34 – 07:35M101 HBA (110-190) Heald / Toribio 8 h 9. May. 2013 19:00 – 03:00 10:38 – 18:39NGC3627/3628 HBA (110-190) Drzazga / Paladino 4 h 19. Mar. 2013 22:00 – 02:30 10:17 – 14:48

4 h 2. Apr. 2013 21:20 – 01:30 10:30 – 14:40IC10 HBA (110-190) Heesen 8 h 25. Aug. 2013 19:00 – 03:00 17:48 – 01:49

LBA (30-88) Heesen 8 h 26. Aug. 2013 19:00 – 03:00 17:48 – 01:49Holmberg 124 HBA (110-190) Nikiel-Wrochzynski --- ---- ---- ----Stephans Quintet HBA (110-190) Nikiel-Wroczynski 8 h 19. Aug. 2013 20:00 – 04:00 18:20 – 02:22

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Cycle-0 Processing/Analysi

s Quite a bit of the MKSP Cycle-0 data is currently

only archived, but not looked at. The problems are manpower and processing

capabilities Processing (data storage) at CEP-1 only guaranteed for

4 weeks. Processing at other places (e.g. Bonn Juelich) possible

but cumbersome. For new observations: include manpower and

processing in your plans from the beginning.

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LOFAR Cycle 1 Next observing cycle for LOFAR Planned to run for 6 months Call for Proposals planned for end of May Deadline: end of August Start of observations: 15. November

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Summary LOFAR is reliably taking science data

Still a lot of manual work but getting better Data quality has improved Still many features missing in the software. Calibration quality is continuously improving

Quick image with basic calibration can be made by the RO Good (state of the art) images take about 9-12 months

dedicated work There is new data available Polarization calibration needs still more work, but I’m

still confident that we’ll manage it with time.

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Questions?

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Discussion: What new observations are needed? Science goals? Who is going to do the work?

Does she/he have the time and experience? Where is the processing going to be done?

Even just moving around the data takes time! LOFAR in three lines:

Total power is possible now. Low noise and/or high resolution is a lot of work. Polarization is even more work.