1. LOFAR Beam Formed (BF) Data & Pipeline Overview September 9, 2010
Anastasia Alexov
& The Pulsar Working Group & ASTRON SW Group

2. Transient Science
Pulsar/Beam-Formed Pipeline has many scientific applications. The following areas of study set the requirements on processing for each of the modes:
Known pulsars - channelization, Stokes Parameters, dedispersion, folding, Radio Frequency Interference (RFI) excision
Pulsar/fast transient survey - channelization, dedispersion [10,000 trial Dispersion Measures (DMs)], RFI excision, searching
Planets, Sun, flare stars - channelization, RFI excision, dynamic spectra, Stokes Parameters
Pulsar
SOHO
Sun

3. LOFAR “Beams” Low Band Antennas (LBA): 10-80MHz
High Band Antennas (HBA): MHz
One to N Stations can be use to observe
Imaging and high time resolution observations can be done simultaneously
High time resolution observing mode will be widely used for Transient Science:
Forming multiple beams is a difficult observing mode
Beam-formed modes trade spatial resolution for time resolution
Pulsar Pipeline effort can be applied to other high timing resolution pipelines
Tied-Array
(Pencil)
Beams
Stations
Element
Station

4. LOFAR “Beams”
Show Movie

5. Beam-Formed Data Flow On-Line TAB Pipeline BF Writer BF Offline

6. Beam-Formed Pipeline Data Flow
On-Line
TAB Pipeline BF
Writer
BF Offline
Pipeline

7. BF -> to -> H5 Writer (bf2h5)
Tied-Array
(Pencil)
Beams
BF Raw and BF TAB data  HDF5 BF file
Need online (BG/P TAB data) and
single-station (raw data only)
versions of bf2h5
BF H5 Structure:
Sub-Array
Pointing
Station
Beams
Element
Beams
Stations

8. Data Packaging Options:
One Table per Subband (1D) [Shown]
One Table for all Subbands (ND)
One Array per Subband (1D)
One Array for all Subbands (ND)

10. Beam-Formed Data Sizes (Challenging)