2015/06/05 by J. Moultaka, A. Eckart, Moultaka, Jihane +2
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.1506.01918
openalex publication_date 2015/06/05 · openalex created_date 2022/10/05 · openalex updated_date 2026/07/28
The close environment of the central supermassive black hole of our Galaxy is\nstudied thoroughly since decades in order to shed light on the behavior of the\ncentral regions of galaxies in general and of active galaxies in particular.\nThe Galactic Center has shown a wealth of structures on different scales with a\ncomplicated mixture of early- and late-type stars, ionized and molecular gas,\ndust and winds. Here we aim at studying the distribution of water ices and\nhydrocarbons in the central parsec as well as along the line of sight. This\nstudy is made possible thanks to L-band spectroscopy. This spectral band, from\n2.8 to 4.2\μ m, hosts important signatures of the circumstellar medium and\ninterstellar dense and diffuse media among which deep absorption features are\nattributed to water ices and hydrocarbons. We observed the Galactic Center in\nthe L-band of ISAAC spectrograph located on UT1/VLT ESO telescope. By mapping\nthe central half parsec using 27 slit positions, we were able to build the\nfirst data cube of the region in this wavelength domain. Thanks to a calibrator\nspectrum of the foreground extinction in the L-band derived in a previous\npaper, we corrected our data cube for the line of sight extinction and\nvalidated our calibrator spectrum. The data show that a residual absorption due\nto water ices and hydrocarbons is present in the corrected data cube. This\nsuggests that the features are produced in the local environment of the\nGalactic center implying very low temperatures well below 80K. This is in\nagreement with our finding of local CO ices in the central parsec described in\nMoultaka et al. (2015).\n