Surveys and Catalogues we use a lot

SDSS – The Sloan Digital Sky Survey started mapping the skies in 1998, and imaged about 30-40% of the sky (call “The SDSS Legacy Imaging Survey”). Then it took spectra of 1 million bright galaxies detected in the images (called the “SDSS Main Galaxy Sample”). Then it did other spectra stuff (like MaNGA below, but various other spectral surveys too).

To learn more about the many surveys and phases of SDSS explore the SDSS website.

SDSS Glossary

  • ugriz – the filters they took images though
  • fiber – part of how the spectra are taken

Galaxy Zoo – morphological analysis of various surveys using crowd sourcing – started in 2007 with the 1 million galaxies in the SDSS Main Galaxy Sample, then did 250,000 brightest ones in more detail (GZ2), then lots of other surveys (e.g. now DECaLS).

Try doing Galaxy Zoo.

Galaxy Zoo Data page – should have all the public morphology catalogues. Sometimes we use pre-release ones though.

Don’t get confused between Galaxy Zoo and Galaxy Zoo: 3D (which is drawing features on MaNGA galaxies) or other crowdsourcing stuff hosted on the Zooniverse. Try some of them if you aren’t sure.

NASA Sloan Atlas (NSA) – catalogue of useful properties of galaxies in SDSS imaging/spectra. NSA data is here, more information on the NSA website (which sometimes breaks because of it’s name).

MaNGA (Mapping Nearby Galaxies at Apache Point Observatory).

Resolved spectral maps of 10,000 galaxies selected out of SDSS data (via the NASA Sloan Atlas). Getting Started with MaNGA

MaNGA sky coverage show below in purple (over grey for the targeting catalog, which is basically the SDSS imaging/GZ2 sky area).

HI-MaNGA (HI followup of MaNGA)

We (as in Masters et al.) followed up MaNGA in HI, by observing anywhere not covered by ALFALFA survey with the Green Bank Radio Telescope. We are still working on making some of this data ready for science (“data reduction”). The sky plot below shows where HI-MaNGA observes, and also shows the footprint of the ALFALFA survey (see below) and some other sky surveys.

ALFALFA (Arecibo Legacy Fast Arecibo L-band Feed Array) Survey

A non-targeted HI survey of all high Galactic latitude sky observable from the Arecibo radio telescope.

Get the data from the ALFALFA website. You’ll most likely want to use the ALFALFA-SDSS cross match table since it already picks the best HI detection for SDSS galaxies, but if you are using DeCALS that won’t make sense as there’s ALFALFA detections outside of the SDSS sky footprint….

DeCALS (Dark energy Camera Legacy Survey)

The DECaLS survey (Dey et al. 2019) uses the Dark Energy Camera (DECam, Flaugher et al. 2015) at the 4m Blanco telescope at Cerro Tololo Inter-American Observatory, near La Serena, Chile.

DECam has a roughly hexagonal 3.2 square degree field of view with a pixel scale of 0.262 arcsec per pixel. The median seeing is 1.0029, 1.0018 and 1.0011 for 𝑔, 𝑟, and 𝑧, respectively.

The Figure below shows the sky coverage of DECaLS imaging which is processed in Galaxy Zoo DECaLS. Here RA is in degrees. RAdeg = 15xRAhrs. So 8hrs (center of MaNGA map above) is 120 deg.