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Title: [Fe II] 1.64 μm IMAGING OBSERVATIONS OF THE OUTFLOW FEATURES AROUND ULTRACOMPACT H II REGIONS IN THE FIRST GALACTIC QUADRANT

We present [Fe II] 1.644 μm features around ultracompact H II regions (UCHIIs) found on a quest for the ''footprint'' outflow features of UCHIIs—the features produced by outflowing materials ejected during an earlier, active accretion phase of massive young stellar objects (MYSOs). We surveyed 237 UCHIIs in the first Galactic quadrant, employing the CORNISH UCHII catalog and UWIFE data, which is an imaging survey in [Fe II] 1.644 μm performed with UKIRT-WFCAM under ∼0.''8 seeing conditions. The [Fe II] features were found around five UCHIIs, one of which was less plausible. We interpret the [Fe II] features to be shock-excited by outflows from YSOs and estimate the outflow mass-loss rates from the [Fe II] flux which are ∼1 × 10{sup –6}-4 × 10{sup –5} M {sub ☉} yr{sup –1}. We propose that the [Fe II] features might be the ''footprint'' outflow features, but more studies are required to clarify whether or not this is the case. This is based on the morphological relation between the [Fe II] and 5 GHz radio features, the outflow mass-loss rate, the travel time of the [Fe II] features, and the existence of several YSO candidates near the UCHIIs. The UCHIIs accompanying the [Fe II]more » features have relatively higher peak flux densities. The fraction of UCHIIs accompanying the [Fe II] features, 5/237, is small when compared to the ∼90% detection rate of high-velocity CO gas around UCHIIs. We discuss some possible explanations for the low detection rate.« less
Authors:
; ; ; ; ;  [1] ; ; ;  [2] ;  [3]
  1. Korea Astronomy and Space Science Institute, 776 Daeduk-daero, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)
  2. Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of)
  3. Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohōkū Place, Hilo, HI 96720 (United States)
Publication Date:
OSTI Identifier:
22340165
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal, Supplement Series; Journal Volume: 214; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CATALOGS; DETECTION; GALAXIES; GHZ RANGE; IMAGES; MASS TRANSFER; STARS; STELLAR WINDS; VELOCITY