This week, I continued to move forward with compiling information for all galaxies within a certain radius of Virgo. We still cannot get the flow model working, so my job was to line match a myriad of catalogs we have. I wrote a python script to do this, and was able to successfully create catalogs for stellar mass, HI content, bulge-to-total mass ratios, UV, and infrared data. Yay!

Our flow model is still a mess. This week, we decided to take a break from trying to decipher the Kim+2016 filament selection criteria, because our issues are certainly not computational in nature. Ignoring the fact that we cannot yet pick out filaments, my goal for the week was to be able to at least cut the Nasa Sloan Atlas table down from ~140,000 galaxies to only the galaxies located within a certain radius of Virgo. I got this program up and running, so it appears that I will have to start trying to match the Kim+2016 paper again. I also spent much of this week trying to understand the nature of cartesian supergalactic coordinates.

My SGY values are still approximately 16 Mpc off from what the Kim+2016 group is using. This week, I was running diagnostic tests on the code to try to isolate what exactly is causing this discrepancy. I was also comparing my numbers for two filament galaxies to those on Nasa's Extragalactic Database (NED). Preliminary results show that NED's numbers are consistent with ours, which is reassuring. We emailed the Kim+2016 group, and their answer appears to have contradicted what was written in their paper. One of our collaborators also emailed us with a suggestion that the Kim+2016 group uses an atypical number for the recession velocity of Virgo, so correcting for this might completely correct our SGY values. Hopefully this can all get figured out soon.

Progress (might have) been made!! I primarily focused on figuring out the Hubble flow model this week, and things are starting to look better. The biggest problem in the past was that our SGY values were way off from what they are in Kim+2016, so when we made SGY cuts to our sample, we had structures in the plot that should not have been there/lacked structures that we were expecting. I played around with this code for a while, and switched to using Virgo-centric coordinates. When I plotted SGZ vs. SGX for Virgo related structures and for the filaments behind Virgo, my figures looked closer to the Kim+2016 figures than they had before. They are still not completely correct, but it's at least a step in the right direction. I'm meeting with Dr. Finn tomorrow, and that will determine what my next step is.

This past week, we skyped with one of our collaborators. We revisited a program that we began to write last semester. The purpose of the code is to recreate the figures from Kim+2016 so we can identify the filaments around Virgo using the same criteria they did. In particular, we want to create a 3-D spatial plot of the region around Virgo, and SGZ vs. SGX plots with cuts in certain SGY regions. Our plots look a little similar to the Kim+2016 plots, but our SGY values are off by approximately 16 Mpc, which is how far away Virgo is from us. This is strange, so we are looking into supergalactic coordinates to try to ensure that we are using them correctly. We are doing this by looking at all of the papers that Kim+2016 cited in reference to the flow model that they used. The Kim+2016 paper is incredibly short, so unfortunately it is not well documented. My plans for this next week are to go through these papers, and to alter our program based on the criteria specified in them to see if our plots look more similar to the Kim+2016 figures. It's going to be a lot of trial and error work, but hopefully we can make some progress.

This past week was primarily a catch-up week for me. When I last intensely worked on this project last semester, I was trying to figure out a Hubble flow model presented by Mould+2000. One of my short-term goals is to recreate plots seen in Kim+2016, a paper that discusses the filamentary environment around Virgo. Much of my time this week was spent working on an annotated bibliography in order to reorient myself. I also began to revisit the Hubble flow model that was giving us problems before the semester break. I am in the process of reading up on galactic coordinate systems and different Hubble flow models. The goal is to understand these in the context of the Virgo cluster. My plans for this coming week are to continue with the annotated bibliography, and to figure out why the plots I created do not exactly match those in Kim+2016. We are skyping a collaborator from NASA/IPAC tomorrow, so hopefully that could give us some insight to what is happening around Virgo.

Hello World! Here is the abstract for my Advanced Lab project-

Title: Identifying Galaxies in Filaments Around Virgo

Abstract:
Galaxies can exist in a myriad of environments throughout the universe. One major difference between these environments is the density of the galactic population. Observations have shown that galaxies in higher density environments, such as clusters and groups, tend to have lower star formation rates than galaxies that exist by themselves in the field. Large galaxy clusters, such as the Virgo cluster, have filaments of galaxies feeding the cluster. Although they are less dense than the cluster, it is possible that these filaments are dense enough to have an impact on the galaxies that pass through them as they fall into the cluster. I will be studying three filaments around the Virgo cluster. I will identify galaxies within the selected filaments using selection criteria found in the literature, and I will cross reference them with CO observations we have taken. I will calculate star-formation rates (SFRs) for these galaxies using Galaxy Evolution Explorer (GALEX) near ultraviolet and WISE infrared observations. I will also compare these filament galaxies to their counterparts in the cluster and field with respect to star-formation rate, atomic gas, and molecular gas content as a function of stellar mass.