ALFA Arecibo 305 m GALSPECT GALFA-HI is a 4′, large area, Galactic HI survey

WNSHS/GAMES WALLABY/GASKAP EBHIS GALFA-HI compared to past, present, future surveys IGPS JEGP+ 11

Arecibo Surveys ALFA SurveysOther instrument surveys PALFAEALFAGALFA ALFALFA ZOA AGESAUDS GALFA-HIGALFACTS GALFA-RRL TOGSTOGS2 I-GALFAPIs (some data taken contemporarily)

GALFA-HI owes a lot of commensal observing!

GALFA-HI DR1 is available to the public. DR2 soon! JEGP+ 11

baseline ripple calibration x crossing- point gain calibration x first sidelobe calibration x

baseline ripple calibration √ crossing- point gain calibration √ first sidelobe calibration √

GALFA-HI matches IRAS and Planck resolutions Extinction HIFIR

GALFA-HI matches IRAS and Planck resolutions Extinction HIFIR

Interstellar morphologies: Cigars, Filaments, Needles Pancakes, Sheets Blobs Even Bicycle Wheels!

GALFA FINDS HI BLOBS

(Ap J, In press)

Both small and weak!

GALFA finds long, straight HI FILAMENTS!

SHEETS are old hat. Consider this famous paper— the earliest known (to me) example of this geometry in the normal ISM…

Here’s our Arecibo Millennium-survey friend 3C225b, showing prominent HI absorption. We measure the temperature (17 K); we use ISM pressure (4000 cm -3 K) to get volume density. N(HI) ~ cm -2 n(HI) ~ 200 cm -3 N(HI)=n(HI) * L WHAT’S L????

Arecibo (GALFA) map of the Knapp ultrathin sheet.

Haud (2010) mapped the narrowest HI emission component: our cold thin cloud is part of a much larger structure, well-fit by an expanding ring! The whole structure is half in, half out of the Local Bubble… Our two ultrathin sheets

A crude sketch of Haud’s rotating, expanding, translating “bicycle wheel in space”, looking down onto the Galaxy…