Year: 2026
Type: preprint
Abstract: Using 10.8 million ``blank'' sky spectra from the DESI Year 3 dataset, we measure the diffuse galactic light (DGL) spectrum in the optical at spectral resolution $R \sim 4000$ by correlating with far-infrared emission from IRAS. Subdividing the sky into 54 deg$^2$ pixels (HEALPix, NSIDE = 8), we map the variation of the DGL correlation spectrum and nebular emission lines across the DESI footprint in the high-Galactic-latitude sky. The increased data volume over previous SDSS-based analyses enables several new detections in the DGL, including scattering both onto and out of the line of sight from neutral interstellar sodium and potassium. We further detect direct emission from ro-vibrational transitions of molecular hydrogen in the near-infrared with an absolute radiance of $0.65\substack{+0.13 \\ -0.12}\times10^{-9}~{\rm erg\, cm^{-2}\,s^{-1}\,sr^{-1}}$, roughly consistent with theoretical expectations, but with an apparent ortho-to-para line ratio that is lower by a factor of $0.60\substack{+0.28 \\ -0.27}$. We confirm previous detections of extended red emission (ERE) in the DGL and map its spatial variation. Our spatially resolved DGL maps provide important observational constraints for the radiative transfer efforts that are now possible with recent 3D models of the Milky Way.
Source: arXiv (Cornell University)
Authors: Saydjari, Andrew K., Draine, Bruce T., Brandt, Timothy D., Schlafly, Edward F., Dey, Arjun, Finkbeiner, Douglas P., Aguilar, J., Ahlen, S., Prieto, C. Allende, Anand, A., Beutler, F., Bianchi, D., Brooks, D., Rosell, A. Carnero, Claybaugh, T., de la Macorra, A., Doel, P., Font-Ribera, A., Forero-Romero, J. E., Gaztañaga, E., Gontcho, Satya Gontcho A, Gutierrez, G., Guy, J., Honscheid, K., Karim, T., Kirkby, D., Kremin, A., Lahav, O., Lambert, A., Landriau, M., Guillou, L. Le, Meisner, A., Miquel, R., Moustakas, J., Nadathur, S., Paillas, E., Percival, W. J., Pérez-Ràfols, I., Prada, F., Ravoux, C., Rossi, G., Samushia, L., Sanchez, E., Saulder, C., Schlegel, D., Schubnell, M., Sharples, R., Silber, J., Siudek, M., Tarlé, G., Weaver, B. A., Zhou, R.
Institutions: Universitat Politècnica de Catalunya, Princeton University, Space Telescope Science Institute, NSF NOIRLab, Boston University, Universidad de La Laguna, Instituto de Astrofísica de Canarias, Inter-University Centre for Astronomy and Astrophysics, University of Milan, Brera Astronomical Observatory, Universidad Nacional Autónoma de México, University College London, Institució Catalana de Recerca i Estudis Avançats, Institute for High Energy Physics, Barcelona Institute of Science and Technology, Fermi National Accelerator Laboratory, Lawrence Berkeley National Laboratory, University of Portsmouth, Sejong University, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Max Planck Institute for Extraterrestrial Physics, Durham University, Institute of Space Sciences, University of Michigan
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Harvard University, Space Telescope Science Institute, Ministerio de Ciencia, Innovación y Universidades, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Office of Science, Science and Technology Facilities Council, Agencia Estatal de Investigación, Division of Astronomical Sciences, FAS Division of Science, Harvard University
Awards: G1044631029, G1105844351, G1286236842, G1632040200, G1813527838, G1863003419, G3452655474, G419881185, G42916606, G433322167, G4501827968, G491712853, G498139845, G5635532810, G58316358, G593054264, G6273510985, G6652958823, G6876926712, Management and Operations of the National Optical Astronomy Observatory, G7395345766, G7805626310, G7863371703, G8497050386, G8667377315
OpenAlex ID: W7204893900