Sravani Vaddi 1, Chris O’Dea 1, Stefi Baum 1, Christine Jones 2, Bill Forman2, Samantha Whitmore 3 and Rabeea Ahmed 3 1 Astrophysical Sciences & Technology, RIT 2 Harvard-Smithsonian Center for Astrophysics 3 Harvard University SRAVANI VADDI, RIT
AGN - Active Galactic Nucleus AGN - Class of galaxies showing energetic phenomena at the center of the galaxy. Proposed by Hoyle and Fowler(1963). Fig: AGN Model SRAVANI VADDI, RIT
MULTI-WAVELENGTH IMAGES OF AGN INFRARED Centaurus A galaxy. Credit: X-ray: Chandra; Radio: VLA; Optical: ESO Hydra A galaxy SRAVANI VADDI, RIT
MOTIVATION Credit: Simon Driver Fig: Galaxy Luminosity Function. Simply a distribution of galaxies Theory predicts large number of bright/massive galaxies. But observations indicate that there are very few bright galaxies. Some mysterious energy is preventing star formation. Galaxy brightness Bright Faint Number density Theory Observations SRAVANI VADDI, RIT
Jets from the AGN prevent cooling of the gas by pushing away the gas. This reduces star formation. Hydra A. Credit: X-ray: Chandra Telescope; Radio: VLA; Optical: Canada-France-Hawaii- Telescope SRAVANI VADDI, RIT POSSIBLE SOLUTION – AGN FEEDBACK
AGN feedback is observed in distant galaxies. THEN, Is it still ongoing? How powerful is AGN activity in the nearby galaxies? How does it affect star formation in these galaxies if at all it does? THE PROJECT SRAVANI VADDI, RIT
Maximum radio power from the AGN is dependent on the mass of the galaxy. Massive galaxies are capable of hosting powerful radio sources. This is consistent with AGN feedback shaping the high mass end of galaxy LF. RESULT 1 – RADIO POWER AND GALAXY MASS RELATION SRAVANI VADDI, RIT
CONCLUSION & FUTURE WORK CONCLUSION We notice that AGN feedback is ongoing in the local universe. AGN activity is not very powerful and prominent in the nearby galaxies as compared to distant galaxies. AGN activity does seem to influence star formation via feedback, BUT, it is not the only process involved in reducing star formation. FUTURE WORK How much feedback is affecting star formation. What are the other processes? Quantitative analysis for this work needs to be done such as calculating star formation rate, efficiency of accretion. SRAVANI VADDI, RIT