PhD Proposal: Karthik Reddy Solipuram
Location
Off Campus : via Webex
Date & Time
April 29, 2020, 7:00 pm – 9:00 pm
Description
ADVISOR: Dr. Markos Georganopoulos
TITLE: X-ray Emission from Powerful Extragalactic Jets: A PhD proposal for Observational Work and Theoretical Modeling
ABSTRACT: Since its launch in 1999, the Chandra X-ray observatory has detected over 150 large scale extragalactic jets. Surprisingly, for many of the powerful jets, the detected X-ray emission is too powerful and/or spectrally too hard to be part of the radio (and optical, when observations exist) spectral component. This strongly suggests a second, high energy spectral component.
These X-rays, the working model argues, can be produced by low energy electrons in the jet that inverse-Compton (IC) scatter the cosmic microwave background (CMB) to X-ray wavelengths. In a simple scenario, this IC/CMB model predicts the X-ray jet to extend past its radio counterpart. However, observations reveal that X-rays decay before the radio in many jets, thereby producing offsets that contradict the IC/CMB model. Alternatively, a second-electron population with energies up to a hundred TeV can produce the X-rays. But such alternative models also do not offer any explanation for these offsets. Despite both kind of models reproducing the observed X-rays, they imply contrasting jet energetics and, in turn, contrasting environmental impacts that have important implications to the evolution of structure in the universe.
The current proposal, divided into two parts, aims at understanding the X-ray emission mechanism of powerful jets and offsets in them. In the first part, we will perform detailed observational and statistical analysis of X-ray-to-radio morphological differences in X-ray jets. Furthermore, we will develop an interactive web dashboard that acts as a clearinghouse for information about all the X-ray jets. In the second part, we will develop a theoretical model where a spinal structure in the jet up-scatters radio emission from an enclosing sheath to produce X-rays, and also an offset. If time permits, we will also investigate the nature of X-ray jets at high redshift where the IC/CMB process can dominate, as the CMB energy density increases as the fourth power of 1+z.
Proposal will be held using Webex.
TITLE: X-ray Emission from Powerful Extragalactic Jets: A PhD proposal for Observational Work and Theoretical Modeling
ABSTRACT: Since its launch in 1999, the Chandra X-ray observatory has detected over 150 large scale extragalactic jets. Surprisingly, for many of the powerful jets, the detected X-ray emission is too powerful and/or spectrally too hard to be part of the radio (and optical, when observations exist) spectral component. This strongly suggests a second, high energy spectral component.
These X-rays, the working model argues, can be produced by low energy electrons in the jet that inverse-Compton (IC) scatter the cosmic microwave background (CMB) to X-ray wavelengths. In a simple scenario, this IC/CMB model predicts the X-ray jet to extend past its radio counterpart. However, observations reveal that X-rays decay before the radio in many jets, thereby producing offsets that contradict the IC/CMB model. Alternatively, a second-electron population with energies up to a hundred TeV can produce the X-rays. But such alternative models also do not offer any explanation for these offsets. Despite both kind of models reproducing the observed X-rays, they imply contrasting jet energetics and, in turn, contrasting environmental impacts that have important implications to the evolution of structure in the universe.
The current proposal, divided into two parts, aims at understanding the X-ray emission mechanism of powerful jets and offsets in them. In the first part, we will perform detailed observational and statistical analysis of X-ray-to-radio morphological differences in X-ray jets. Furthermore, we will develop an interactive web dashboard that acts as a clearinghouse for information about all the X-ray jets. In the second part, we will develop a theoretical model where a spinal structure in the jet up-scatters radio emission from an enclosing sheath to produce X-rays, and also an offset. If time permits, we will also investigate the nature of X-ray jets at high redshift where the IC/CMB process can dominate, as the CMB energy density increases as the fourth power of 1+z.
Proposal will be held using Webex.
