Aligned Molecular Clouds towards SS433 and L=348.5 degrees; Possible Evidence for Galactic "Vapor Trail" Created by Relativistic Jet

Abstract

We have carried out a detailed analysis of the NANTEN 12CO(J=1-0) dataset in two large areas of ~25 square degrees towards SS433 (l~40 degree) and of ~18 square degrees towards l~348.5 degree, respectively. We have discovered two groups of remarkably aligned molecular clouds at |b|~1--5 degree in the two regions. In SS433, we have detected 10 clouds in total, which are well aligned nearly along the axis of the X-ray jet emanating from SS433. These clouds have similar line-of-sight velocities of 42--56 km s^-1 and the total projected length of the feature is ~300 pc, three times larger than that of the X-ray jet, at a distance of 3 kpc. Towards l~348.5 degree, we have detected four clouds named as MJG348.5 at line-of-sight velocities of -80 -- -95 km s^-1 in V_LSR, which also show alignment nearly perpendicular to the Galactic plane. The total length of the feature is ~400 pc at a kinematic distance of 6 kpc. In the both cases, the CO clouds are distributed at high galactic latitudes where such clouds are very rare. In addition, their alignments and coincidence in velocity should be even rarer, suggesting that they are physically associated. We tested a few possibilities to explain these clouds, including protostellar outflows, supershells, and interactions with energetic jets. Among them, a favorable scenario is that the interaction between relativistic jet and the interstellar medium induced the formation of molecular clouds over the last ~10^5-6 yrs. It is suggested that the timescale of the relativistic jet may be considerably larger, in the order of 10^5-6 yrs, than previously thought in SS433. The driving engine of the jet is obviously SS433 itself in SS433, although the engine is not yet identified in MJG348.5 among possible several candidates detected in the X-rays and TeV gamma rays.

29 pages, 10 figures, already published in PASJ, 2008,60, 715

References in corpus (5)

• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• Stellar Explosions by Magnetic Towers
• The Distance to SS433/W50 and its Interaction with the ISM
• Magnetic interaction of jets and molecular clouds in NGC 4258
• Large Scale CO Observations of a Far-Infrared Loop in Pegasus; Detection of a Large Number of Very Small Molecular Clouds Possibly Formed via Shocks

Cited by in corpus (21)

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• A peculiar jet and arc of molecular gas toward the rich and young stellar cluster Westerlund 2 and a TeV gamma ray source
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• Multi-wavelength environment of the Galactic globular cluster Terzan 5
• Continuous Jets and Backflow Models for the Formation of W50/SS433 in Magnetohydrodynamics Simulations
• Discovery of possible molecular counterparts to the infrared Double Helix Nebula in the Galactic center
• Magneto-hydrodynamic Simulations of a Jet Drilling an HI Cloud: Shock Induced Formation of Molecular Clouds and Jet Breakup
• A Small-Scale Investigation of Molecular Emission toward the Tip of the Western Lobe of W50/SS433
• Spatially resolved study of the SS 433/W50 west region with Chandra: X-ray structure and spectral variation of non-thermal emission
• The jet and arc molecular clouds toward Westerlund 2, RCW 49, and HESS J1023-575; 12CO and 13CO (J=2-1 and J=1-0) observations with NANTEN2 and Mopra Telescope
• Energy estimation of high energy particles associated with the SS433/W50 system through radio observation at 1.4 GHz
• Molecular clouds at the eastern edge of radio nebula W50
• The Eastern Filament of W50
• Microquasar jet-cocoon systems as PeVatrons
• Physical properties of the molecular cloud, N4, in SS433; Evidence for an interaction of molecular cloud with the jet from SS433
• A study of the interstellar medium towards the unidentified dark TeV $\gamma$-ray sources HESS J1614-518 and HESS J1616-508
• Magnetohydrodynamic Simulations of the Formation of Molecular Clouds toward the Stellar Cluster Westerlund 2: Interaction of a Jet with Clumpy Interstellar Medium
• Near-Ultraviolet Radiation toward Molecular Cloud N4 in W 50/SS 433: Evidence for Direct Interaction of the Jet with Molecular Cloud
• Discovery of CO Clouds Associated with the X-ray Jets of SS 433: Evidence for Shock-Cloud Interaction Enhancing Nonthermal X-ray Emission