I-GALFA: The Inner-Galaxy ALFA H I Survey

Bon-Chul Koo, Geumsook ParkJi-hyun Kang

Kevin DouglasJosh Peek

Eric Korpela, Carl HeilesTom Bania

Seoul National U.NAICExeter U.Columbia U.U. Cal-BerkeleyBoston U.

Steven Gibson W. Kentucky U.

Arecibo Surveys Workshop, NAIC, December 10, 2009

I-GALFA Overview Quick (2-year) lean (8-member) survey Map inner Galactic disk H I (330 hrs, 1100 deg2)

GALFA H I spectrometer, methods, pipeline Base Trms ~ 0.25 K for 3.35’ beam, 0.184 km/s chan.

Science Molecular cloud formation Shells + chimneys related to massive star energetics Detailed structure of Galaxy, on and off plane

Commensal partners: ZOA + GALFACTS

Thanks to NAIC for scheduling!

I-GALFA Sky Coverage

Completed in 2009 September!

Will merge with other GALFA - H I surveys

RA+DEC fields covering |GLAT| < 10 degrees over full AO DEC range 4 major fields (ZA nod on meridian, 0.84’/s) 1 ``zenith’’ field (AZ wag 51m W of zenith, 0.59’/s)

Some latitude extensions due to CIMA quirks and schedule resolution – all useful!

I-GALFA Commensality

First doubly-commensal ALFA survey project I-GALFA (a2186) was primary (GALSPECT) ZOA (a2144) + GALFACTS (a2390) commensal

shared WAPPs in 2008, Mocks in 2009 GALFACTS pipeline bins time samples for ZOA data

Commensal needs + challenges GALFACTS: rapid sampling, radar RFI filter, winking cal ZOA: fine spectral resolution, good redshift coverage

Commensal benefits Time efficiency CIMA development (fastbasket 2006-2008, smartbasket 2009) Same methods now used for GALFACTS (a2130) + TOGS2

I-GALFA Observing

Procedures adapted from Perseus (a2174) and other GALFA - H I projects

Testing / hairy observations handled by obs. team Routine observations by telescope operators Each session assigned an obs. team member:

Prepare observing scripts for operator to run On call during run in case of problems Run daily bookkeeping scripts, update logs, etc.

All sessions logged on I-GALFA website

I-GALFA Data

Processing team (Douglas, Kang, Peek) ran GSR pipeline on all GALSECT data Challenges near plane spur pipeline development

(broader lines, brighter emission) Data still being improved in next few months

Processed data assembled in cubes (Gibson) Currently proprietary to science team Initial public release in 2010; full release in 2011 I2 ‘narrow’ and ‘wide’ copies of each cube (1 GB) R4 full-spectrum cubes eventually (8 GB) Both RA+DEC and GLON+GLAT coordinates

I-GALFA and the NVO

Public release data to be on GALFA - H I website Cornell + other sites (?) -- redundancy is good! Useful NVO interface features

Level 1: pre-generated atlas tile cubes (list or map) Level 2: cutout image cubes on same atlas pixel grid Level 3: arbitrary mosaic cubes regridded from atlas Ancillary Data:

2-D cube projections [(l,b), (l,v), etc.] of I-GALFA H I NVO hooks to other ALFA data (e.g. GALFACTS, RRL) NVO hooks to multi-data (e.g., SkyView)

First I-GALFA Science: Gas Structures

First I-GALFA Science: Gas Structures

500 pc

First I-GALFA Science: Gas Structures

Distance ~ 3 kpc

=> 3.4’ ~ 3 pc

NGC 891 Optical Dust Worms

Distance ~ 9.5 Mpc

Ground 1” ~ 48 pc

HST 0.05” ~ 2.4 pc

(H I has velocity!)

(WIYN 3.5m; Howk & Savage 1997)

First I-GALFA Science: Cold H I Emission

Newly forming disk-halo molecular clouds?

First I-GALFA Science: H I Self-Absorption

Riegel-Crutcher Cold Cloud fragments?

Downes et al (1981) polarized continuumGALFACTS polarimetry pending

Supershell GSH 041+01+27Multiple SNe or HVC Colliding with Disk

H I Structure: Inner vs. Outer Galaxy In the inner Galaxy, small filamentary structures

perpendicular to the plane dominate. In the outer Galaxy, long filaments parallel to the plane

dominate. Massive stars, turbulence? Power spectrum?

Inner galaxy at +80 km/s Outer galaxy at -80 km/s

I-GALFA Publications, etc.

Koo et al., 2009, IAU Special Session 8 on Galactic plane, Highlights of Astronomy, in press (survey overview talk)

Gibson et al., in preparation for AJ (survey technical paper) Forthcoming science papers (2010)

Gibson et al., in prep for ApJ (cold H I and H2 in extraplanar clouds) Koo et al., in prep for ApJ (disk-halo H I whiskers + filaments) Kang et al., in prep for ApJ (forbidden velocity wing H I shells) Sidorin et al., in prep for A&A (H I analogs of GLIMPSE IR shells) Douglas et al., in prep for ApJ (gas-dust relations in extraplanar clouds)

Ph.D. theses in progress: Geumsook Park, Vojtech Sidorin Undergrad research: Sean Stopher, Aaron Bell Outreach: public talks on Arecibo using GALFA images – WKU

student clubs, gifted Kentucky high school students, etc.

Acknowledgements

Telescope operators: Israel Cabrera, Edgardo Cruz, Norberto Despiau, Elliot Gonzalez, Juan Marrero, Wilfredo Portalatin

Other NAIC staff: Mikael Lerner, Phil Perillat, Arun Venkataraman, Ganesan Rajagopalan, Hector Hernandez, and many others

ZOA + GALFACTS commensal partners: Trish Henning, Robert Minchin, Russ Taylor, Chris Salter, Tapasi Ghosh, Jeff Dever, Jeroen Stil, and many others

GALFA - H I scripts, pipeline: Peek, Heiles, Stanimirovic, Krco I-GALFA observing team: Koo, Kang, Park, Korpela, Gibson I-GALFA data team: Douglas, Kang, Peek, Gibson Grants from NSF, Korean Research Foundation, Marie Curie

fellowship

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