Morphological Evidence for the eROSITA Bubbles Being Giant and Distant Structures

Abstract

There are two contradictory views of the eROSITA bubbles: either a 10 kpc-scale pair of giant bubbles blown by the Galactic center (GC), or a 100 pc-scale local structure coincidentally located in the direction of GC. A key element of this controversy is the distance to the bubbles. Based on the 3D dust distribution in the Galactic plane, we found three isolated, distant (500-800 pc) clouds at intermediate Galactic latitudes. Their projected morphologies perfectly match the X-ray shadows on the defining features of the north eROSITA bubble, i.e., the North Polar Spur (NPS) and the Lotus Petal Cloud (LPC), indicating that both the NPS and LPC are distant with a distance lower limit of nearly 1kpc. In the X-ray dark region between the NPS and LPC, we found a few polarized radio arcs and attributed them to the bubble's shock front. These arcs match up perfectly with the outer border of the NPS and LPC and provide a way to define the bubble's border. The border defined in this way can be well described by the line-of-sight tangent of a 3D skewed cup model rooted in the GC. We conclude that, instead of being two independent, distant features, NPS and LPC compose a single, giant bubble, which, therefore, is most plausibly a 10-kpc scale bubble rooted at the GC.

arXiv commentAccepted for publication in ApJL. 11 pages, 5 figures

References in corpus (28)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• The eROSITA X-ray telescope on SRG
• Calibration of X-ray absorption in our Galaxy
• The SRG/eROSITA all-sky survey: First X-ray catalogues and data release of the western Galactic hemisphere
• The eROSITA Final Equatorial Depth Survey (eFEDS): The X-ray catalog
• Detection of large-scale X-ray bubbles in the Milky Way halo
• Updated Gaia-2MASS 3D maps of Galactic interstellar dust
• Resolving nearby dust clouds
• Magnetic fields in supernova remnants and pulsar-wind nebulae
• Three-dimensional extinction maps: Inverting inter-calibrated extinction catalogues
• Evidence for Gamma-ray Jets in the Milky Way
• The Trouble with the Local Bubble
• S-band Polarization All Sky Survey (S-PASS): survey description and maps
• The large-scale ionization cones in the Galaxy
• Optical Polarization Mapping toward the interface between the Local Cavity and Loop I
• Faraday Tomography of the North Polar Spur: Constraints on the distance to the Spur and on the Magnetic Field of the Galaxy
• Local ISM 3D distribution and soft X-ray background: Inferences on nearby hot gas and the North Polar Spur
• Unveiling the Origin of the Fermi Bubbles
• The North Polar Spur and Aquila Rift
• Tracing the Milky Way Nuclear Wind with 21cm Atomic Hydrogen Emission
• On the distance to the North Polar Spur and the local CO-H2 factor
• Possible connection between the asymmetry of North Polar Spur and Loop I with Fermi Bubbles
• Constraining the Distance to the North Polar Spur with Gaia DR2
• A Unified Model for the Fan Region and the North Polar Spur: A bundle of filaments in the Local Galaxy
• Interaction of the Galactic-Centre Super Bubbles with the Gaseous Disc
• Misaligned jets from Sgr A${}^{\ast }$ and the origin of Fermi/eROSITA bubbles
• Giant HI Hole inside the 3-kpc Ring and the North Polar Spur - The Galactic Crater -

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