GALFA-HI DR2 — data access

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Click a cube to select it · shift-drag (or the dashed-box tool) to draw a cutout · R.A. wraps continuously

Background

cube footprints Galactic plane

Product set

Narrow 0.184 km/s · ±188 km/s Wide 0.736 km/s · ±754 km/s

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Cutout

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Centre R.A. (deg)

Centre Dec (deg)

Width (deg)

Height (deg)

v_LSR low (km/s)

v_LSR high (km/s)

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Each cutout carries HISTORY cards naming the source cubes, the data DOIs and the survey paper.

Cube	Set	R.A. centre	Dec centre	Footprint	Size	Download

Declination centres are 2.35°, 10.35°, 18.35°, 26.35° and 34.35°. The DR2 paper's link tables print these truncated to +02, +10 and so on; the values here come from the FITS headers.

About these data

GALFA-HI DR2 maps Galactic neutral hydrogen over 13,146 square degrees — 4 steradians, 32% of the sky — at 4′ angular resolution and 0.184 km s⁻¹ channel spacing, with a median noise of 150 mK per 1 km s⁻¹ channel.

Products

Narrow cubes: 225 cubes, 0.184 km/s channels over |v_LSR| ≤ 188.4 km/s.
Wide cubes: 225 cubes, 0.736 km/s channels over |v_LSR| ≤ 753.8 km/s.
Column density maps: Far-sidelobe stray-radiation-corrected N_HI, with the uncorrected map and the correction itself, over four velocity intervals.

Each cube is 512′ × 512′ on a 1′ Cartesian R.A.–Dec grid, 512 × 512 × 2048 pixels stored as 16-bit integers with BSCALE = 0.008, 1.07 GB per file. Neighbouring cubes overlap by 32′ and agree bit-for-bit in the overlap.

Sky map backgrounds

HI: GALFA-HI DR2 stray-radiation-corrected N_HI over |v_LSR| ≤ 90, +90 to +400 and −400 to −90 km/s, at the survey's native 1′ sampling.
Optical: DSS2 colour (STScI, Caltech, AAO), read from the ESA ESASky HiPS mirror and resampled to 1′.
CO: Planck PR2 CO(1–0) “Type 2” map (Planck Collaboration 2016, A&A 594, A10), bilinearly interpolated from N_side = 2048.
Dust: E(B−V) from Schlegel, Finkbeiner & Davis (1998), ApJ 500, 525, uncorrected; bilinear from the 4096² polar maps.

Every background is resampled onto the survey's own 1′ R.A.–Dec grid, so footprints and cutout boxes line up with them pixel for pixel. They are for orientation; use the original data products for measurement. The |v| ≤ 90 km/s N_HI map is also published as a FITS HiPS for Aladin at https://data.galfa-hi.space/hips/dr2/nhi-srcorr-m90p90/v1.

Citation

Peek, J. E. G., Babler, B. L., Zheng, Y., Clark, S. E., Douglas, K. A., Korpela, E. J., Putman, M. E., Stanimirović, S., Gibson, S. J., & Heiles, C. 2018, The GALFA-HI Survey Data Release 2, ApJS, 234, 2.

doi:10.3847/1538-4365/aa91d3

Archival copies

Wide cubes — 10.7910/DVN/X4PQ1Z
Narrow cubes — 10.7910/DVN/MFM8C7
Column density maps — 10.7910/DVN/T9CFT8
Rolling Hough Transform — 10.7910/DVN/BEQ9ZZ
Reduction pipeline — 10.5281/zenodo.1009153

Harvard Dataverse holds the system of record. This site is a service layer over an archival copy.