The Unusual Galactic Center Radio Source N3

Abstract

Here we report on new, multi-wavelength radio observations of the unusual point source "N3" that appears to be located in the vicinity of the Galactic Center. VLA observations between 2 and 50 GHz reveal that N3 is a compact and bright source (56 mJy at 10 GHz) with a non-thermal spectrum superimposed upon the non-thermal radio filaments (NTFs) of the Radio Arc. Our highest frequency observations place a strict upper limit of 65 x 28 mas on the size of N3. We compare our observations to those of Yusef-Zadeh & Morris (1987) and Lang et al. (1997) and conclude that N3 is variable over long time scales. Additionally, we present the detection of a compact molecular cloud located adjacent to N3 in projection. CH3CN, CH3OH, CS, HC3N, HNCO, SiO, SO, and NH3 are detected in the cloud and most transitions have FWHM line widths of ~20 km/s. The rotational temperature determined from the metastable NH3 transitions ranges from 79 K to 183 K depending on the transitions used. We present evidence that this molecular cloud is interacting with N3. After exploring the relationship between the NTFs, molecular cloud, and N3, we conclude that N3 likely lies within the Galactic Center. We are able to rule out the HII region, young supernova, active star, AGN, and micro-quasar hypotheses for N3. While a micro-blazar may provide a viable explanation for N3, additional observations are needed to determine the physical counterpart of this mysterious source.

arXiv commentAccepted for publication in The Astrophysical Journal. 19 pages, 11 figures

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Cited by in corpus (10)

• A Census of Early Phase High-Mass Star Formation in the Central Molecular Zone
• Statistical Properties of the Population of the Galactic Center Filaments: The Spectral Index and Equipartition Magnetic Field
• A VLA Polarimetric Study of the Galactic Center Radio Arc: Characterizing Polarization, Rotation Measure, and Magnetic Field Properties
• M0.20-0.033: An Expanding Molecular Shell in the Galactic Center Radio Arc
• A Centimeter-wave Study of Methanol and Ammonia Isotopologues in Sgr B2(N): Physical and chemical differentiation between two hot cores
• The CARMA 3mm Survey of the Inner $0.7^{\circ }\times 0.4^{\circ }$ of the Central Molecular Zone
• 2 mm GISMO Observations of the Galactic Center. II. A Nonthermal Filament in the Radio Arc and Compact Sources
• A transient, flat spectrum radio pulsar near the Galactic centre
• Evidence for an interaction between the Galactic Center clouds M0.10-0.08 and M0.11-0.11
• 6.7 GHz CH3OH absorption towards the N3 Galactic Center point-source