DIISC-I: The Discovery of Kinematically Anomalous Hi Clouds in M 100

Hansung B. Gim, Sanchayeeta Borthakur, Emmanuel Momjian, Mansi Padave, Rolf A. Jansen, Dylan Nelson, Timothy M. Heckman, Robert C. Kennicutt, Andrew J. Fox, Jorge L. Pineda, David Thilker, Guinevere Kauffmann, Jason Tumlinson

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We report the discovery of two kinematically anomalous atomic hydrogen (H i) clouds in M 100 (NGC 4321), which was observed as part of the Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium (DIISC) survey in H i 21 cm at 3.3 km s-1 spectroscopic and 44″ × 30″ spatial resolution using the Karl G. Jansky Very Large Array.15 These clouds were identified as structures that show significant kinematic offsets from the rotating disk of M 100. The velocity offsets of 40 km s-1 observed in these clouds are comparable to the offsets seen in intermediate-velocity clouds (IVCs) in the circumgalactic medium (CGM) of the Milky Way and nearby galaxies. We find that one anomalous cloud in M 100 is associated with star-forming regions detected in Hα and far-ultraviolet imaging. Our investigation shows that anomalous clouds in M 100 may originate from multiple mechanisms, such as star formation feedback-driven outflows, ram pressure stripping, and tidal interactions with satellite galaxies. Moreover, we do not detect any cool CGM at 38.8 kpc from the center of M 100, giving an upper limit of N(H i) ≤1.7 × 1013 cm-2 (3σ). Since M 100 is in the Virgo cluster, the nonexistence of neutral/cool CGM is a likely pathway for turning it into a red galaxy.

Original languageEnglish (US)
Article number69
JournalAstrophysical Journal
Issue number1
StatePublished - Nov 20 2021

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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