Astronomy Colloquia at Caltech for 2016-17

Colloquia are held every Wednesday during the academic year at 4pm in the Cahill Hameetman auditorium.
Wine and cheese will be served in the Cahill Foyer from 5-5:30pm.

Month
Date
Speaker

Talk Title
SEPTEMBER 28
Rob Simcoe
MIT-Kavli Institute & Radcliff Institute for Advanced Study

Host: A. Sargent

Heavy Element Enrichment in Early Circumgalactic and Intergalactic
Environmnents

Using the FIRE spectrometer at Magellan, we have gathered deep IR spectra of 40 quasars at z > 5.8 and over 100 at z > 4, providing at last a statistically significant pathlength for studying intervening
heavy-element absorption systems near the epoch of reionization.  I will discuss the status of these absorption measurements, with particular emphasis on detections at z > 5.5.  These relatively rare
absorbers have the potential to place joint bounds on heavy element pollution and the ionizing background radiation field at early times.  I will describe how high resolution optical and IR measurements may be combined to constrain these systems' gas-phase metallicity, even when Gunn-Peterson absorption saturates the HI profiles into an unusuable condition.  I will close with some discussion of future prospects for
this work using instruments for existing telescopes and ELTs.

OCTOBER 5



No Colloquium

12
Julie Comerford
U. Colorado

Host: R. Chary

AGN Triggering in Galaxy Mergers as Traced by Dual AGN and Offset AGN

Galaxy mergers drive central inflows of gas, which are an important triggering mechanism for AGN.  Kpc-scale separation supermassive black hole pairs in ongoing galaxy mergers are ideal tracers of this link between galaxy mergers and AGN.  In dual AGN systems both black holes are fueled as AGN, whereas in offset AGN systems only one of the black holes is an AGN.  I will present multiwavelength approaches to building catalogs of dual AGN and offset AGN, and show the results of our observing campaigns with HST, Chandra, VLA, and Keck.  Finally, I will discuss what our results show about whether galaxy mergers preferentially fuel the most luminous AGN, which black hole in a merger is more efficient at accreting gas, and where in a merger the AGN fueling occurs.

19
Kevin France
U. Colorado

Host: G. Hallinan



26
Vikram Ravi
Caltech

Host:



NOVEMBER
02
Ondrej Pejcha
Princeton

Host: J. Fuller



09
Speaker
Institute

Host:



16
Andrew Fabian
Cambridge

Host: A. Sargent



23


No Colloquium: Thanksgiving Holiday
30
Speaker
Institute

Host:



DECEMBER 28


No Colloquium: Christmas Holiday
JANUARY 4



No Colloquium: AAS meeting

11

Speaker
Institute

Host:



18

Speaker
Institute

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25

Speaker
Institute

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FEBRUARY
1

Speaker
Institute

Host:



8

Speaker
Institute

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15

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22

Speaker
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MARCH
1

Speaker
Institute

Host:



8

Speaker
Institute

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APRIL
5

Speaker
Institute

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12

Speaker
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19

Speaker
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26

Speaker
Institute

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MAY
3

Speaker
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10

Speaker
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17

Speaker
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24

Speaker
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31

Speaker
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Information for Speakers

Previous Astronomy Colloquia:


Updated: