MS Arshia Jacob & Chaoli Zhang

/MS Arshia Jacob & Chaoli Zhang

MS Arshia Jacob & Chaoli Zhang

Event Details

Speaker: Arshia Jacob, Chair: Felix Pötzl

Title: The search for CH isotopes and understanding the elusive nature of CH2

The hydride story continues, but this time in a search for the
isotope of CH, 13CH and understanding the origins of CH2 emission. In my talk
today I will present the first detection of 13CH in the interstellar medium
and discuss its importance in bench-marking the 12C/13C Galactic gradient.
Further I would also like to discuss our recent detections of CH2 towards star
forming regions with associated PDRs. As an early product of ion-molecule gas
phase chemistry, CH2 plays an important role in interstellar chemistry and was
first detected towards the Orion and W51 star-forming regions by Hollis et al.
1995. Given their high energies above the ground (215 K) they were thought to
arise in dense, hot regions near newly formed stars, however an origin in hot
photodissociation regions (PDRs) still remains a possibility. Combined with
carbon radio-recombination line (CRRL) data at comparable angular resolution
we show that the elusive CH2 emission may indeed have origins in a hot, dilute

Speaker: Chaoli Zhang, Chair: Arshia Jacob

Title: High Redshift Galaxy Groups As Seen by ATHENA

By 2031, it is expected that our cosmological model, which describes the evolution of the Universe, will be tightly constrained from projects such as the eROSITA and Euclid satellite missions. However, major astrophysical questions related to the formation and evolution of the largest collapsed structures, namely galaxy groups and clusters, will remain open.

ATHENA will help to answer the questions of how and when the first galaxy groups in the Universe, massive enough to bind more than 10^7 K gas, formed. In this work, we use a state-of-the-art SIXTE simulator to investigate the ATHENA detection capabilities of the early galaxy groups (0.5 < z < 4) by using wavelet-based detection algorithm. The simulations take into account the main ATHENA instrumental features: background, vignetting and PSF degradation with off-axis angle. Since little is known about the thermo-dynamical state of such groups, different physically motivated models are simulated and tested. Our detailed simulations show such galaxy groups can be detected with high probability as extended sources by ATHENA.