Top Banner
Herschel Open Time Cycle 1 DP workshop ESAC, 16-18 March 2011 - page 1 Pat Morris, NHSC Pat Morris, NHSC HIFI Mapping HIFI Mapping Processing in HIPE Processing in HIPE
9

HIFI Mapping Processing in HIPE

Jan 21, 2016

Download

Documents

raiden

HIFI Mapping Processing in HIPE. Pat Morris, NHSC. HIFI maps. HIFI spectral maps come in two main flavors On The Fly “Standard” Position Switch Frequency Switch with or without position switch Load Chop with or without position switch Dual Beam Switch Fast or normal chop - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: HIFI Mapping Processing in HIPE

Herschel Open Time Cycle 1 DP workshop

ESAC, 16-18 March 2011

- page 1

Pat Morris, NHSCPat Morris, NHSC

HIFI MappingHIFI MappingProcessing in HIPEProcessing in HIPE

Page 2: HIFI Mapping Processing in HIPE

- page 2

HIFI maps

• HIFI spectral maps come in two main flavors

– On The Fly• “Standard” Position Switch• Frequency Switch with or without position switch• Load Chop with or without position switch

– Dual Beam Switch • Fast or normal chop• With or without special timings for optimal continuum

stability

• Each have their own pathologies that make it worthwhile to perform some combination of pipeline re-run, data cleanup, and re-gridding.

• The first step is data inspection.

Page 3: HIFI Mapping Processing in HIPE

- page 3

Identifying the mode type

• To confirm your observation’s observing mode, or when you take data from the public archive, look in the meatData of the obsContext:

• In particular you should note if the data come from the “noRef” total power mode with FSwitch or LoadChop, meaning that a sky reference was skipped. E.g.– HifiMappingModeOTFFSwitchNoRef– HifiPointModeLoadChopNoRef– HifiSScanModeFSwitchNoRef

NoRef will result in standing waves in the data, potentially strong

Page 4: HIFI Mapping Processing in HIPE

- page 4

Reasons to reprocess

• Level 0 pipeline– Astrometry is assigned to H and V beams data with HIPE ≥ v5.0

• Level 1 – pipelineLoadChop and FSwitch data quality improved by reversing order of

doHotCold.

– Deselect one OFF phase in DBS Raster if contaminated.

• Data cleanup– Removal of residual standing waves and/or baseline drift before gridding

• Level 2: Regridding– Redefine “pixel” size consistent with the actual spacing of lines and

readouts– Redefine according to your data’s S/N – Or change sampling and convolution kernel to match and compare with

other maps (different frequencies or beam sizes).

• Combine maps – H with V from the same observation– Maps from different observations at same (or almost same) frequencies

Page 5: HIFI Mapping Processing in HIPE

- page 5

340, 98 MHz period sine waves removed

(fitHifiFringe)

Baseline Cleanup Example: OTF Map 7b

Level 2 product: Residual standing waves, strong baseline drift

Smoothed baselines removed

Instrument signatures convolved into spectral cube

Cube regridded from cleaned HTP

Page 6: HIFI Mapping Processing in HIPE

- page 6

HSpot parameters

04/21/23 6DPUG 24, MPE - page

Certain key map information needs to be passed to the gridding task:

# readouts, # scan legs mapsize (pixels2)Readout spacing, leg spacing pix size (arcsec)

Also here, noise estimates are not transferred to associated data products for reference to observed noise properties. Applies to ALL modes.

Page 7: HIFI Mapping Processing in HIPE

- page 7

H + V maps combined

04/21/23 7DPUG 24, MPE - page

S/N is given to the user in HSpot assuming both beams are combined (true of all AOT modes).

This will be available with the gridding task in HIPE 6.0.

Can be done fairly easily with a script, but • metaData are not yet properly handled. • Memory can be a factor with large maps.

Page 8: HIFI Mapping Processing in HIPE

- page 8

CH+ vs methanol

• Distribution of methanol is localized to the IRc2 / Compact Ridge region.

High density hot core region, n(H2) ~few 105 – 106 Able to support some C+ formation in J shocks? Methanol and CH+ strength generally anti-

correlate.

Methanol line intensity

CH+ 9 km/s

Page 9: HIFI Mapping Processing in HIPE

- page 9

Normalized intensityCH3OH CH+ C+