Broadband VLA Spectral Line Survey of a Sample of Ionized Jet Candidates

Abstract

The study of the interaction between ionized jets, molecular outflows and their environments is critical to understanding high-mass star formation, especially because jets and outflows are thought to be key in the transfer of angular momentum outwards from accretion disks. We report a low-spectral resolution VLA survey for hydrogen radio recombination lines, OH, NH${}_3$, and CH${}_3$OH lines toward a sample of 58 high-mass star forming regions that contain numerous ionized jet candidates. The observations are from a survey designed to detect radio continuum; the novel aspect of this work is to search for spectral lines in broadband VLA data (we provide the script developed in this work to facilitate exploration of other datasets). We report detection of 25GHz CH${}_3$OH transitions toward ten sources; five of them also show NH${}_3$ emission. We found that most of the sources detected in CH${}_3$OH and NH${}_3$ have been classified as ionized jets or jet candidates and that the emission lines are coincident with, or very near ($\lesssim 0.1$ pc) these sources, hence, these molecular lines could be used as probes of the environment near the launching site of jets/outflows. No radio recombination lines were detected, but we found that the RMS noise of stacked spectra decreases following the radiometer equation. Therefore, detecting radio recombination lines in a sample of brighter free-free continuum sources should be possible. This work demonstrates the potential of broadband VLA continuum observations as low-resolution spectral line scans.

38 pages, 19 figures. Accepted for publication in The Astrophysical Journal Supplement Series

References in corpus (19)

• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Class I methanol masers in the outflow of IRAS 16547-4247
• Weak and Compact Radio Emission in Early High-Mass Star Forming Regions: I. VLA Observations
• Hot ammonia in NGC6334I & I(N)
• Online Database of Class I Methanol Masers
• Survey of Water and Ammonia in Nearby galaxies (SWAN): Resolved Ammonia Thermometry, Water and Methanol Masers in the Nuclear Starburst of NGC 253
• Protostellar Outflows at the EarliesT Stages (POETS). II. A possible radio synchrotron jet associated with the EGO G035.02+0.35
• A Galactic survey of radio jets from massive protostars
• A catalog of 44 GHz methanol masers in massive star-forming regions. IV. The high-mass protostellar object sample
• Survey of Ionized Gas of the Galaxy, Made with the Arecibo telescope (SIGGMA): Inner Galaxy Data Release
• An H2CO 6cm Maser Pinpointing a Possible Circumstellar Torus in IRAS18566+0408
• VLA Survey of Dense Gas in Extended Green Objects: Prevalence of 25 GHz Methanol Masers
• Hot Ammonia around Young O-type Stars. II. JVLA imaging of highly-excited metastable ammonia masers in W51-North
• LineStacker: A spectral line stacking tool for interferometric data
• Hot Ammonia in the Center of the Seyfert 2 galaxy NGC 3079
• Multiple molecular outflows and fragmentation in the IRDC core G34.43+00.24 MM1
• VLA Observations of 9 Extended Green Objects in the Milky Way: Ubiquitous Weak, Compact Continuum Emission, and Multi-Epoch Emission from CH${}_3$OH, H${}_2$O, and NH${}_3$ Masers
• Discovery of ammonia (9,6) masers in two high-mass star-forming regions
• High-Sensitivity Observations of Molecular Lines with the Arecibo Telescope