# VirgoFilament

## Introduction

Observations and models of overall large scale structure of the universe have shown that dark matter arranges itself into web-like filamentary structures. These filaments of dark matter attract baryonic matter, allowing structures to form. These structures can dramatically range from being sparsely populated to having high density populations of galaxies. The largest gravitationally bound structures in the universe are galaxy clusters, and they fall on the high density end of the spectrum of possible galactic environments. Since they form along dark matter filaments, galaxy clusters are typically surrounded by a network of galaxy filaments. Filaments around clusters are the pathways by which galaxies transition into cluster members, and they could possibly play a large role in the evolution of galaxies in the cluster environment.

Much work has been done to try to understand how a galaxy’s environment influences its evolution. Galaxies observed in clusters and other high density environments are commonly ”red and dead,” or quiescent. This shows that the higher density environments can impose harsh environmental processes on member galaxies that will cause star formation to quench. The leading culprits for quenching in cluster member galaxies are intracluster medium-interstellar medium interactions (ram pressure stripping), starvation/strangulation, and tidal interactions between galaxies in the cluster. However, this analysis of environmentally-driven quenching has neglected to acknowledge the role filaments play in the transition of a galaxy from a low to high density environment. Since galaxies pass through filaments as they infall towards a cluster, it is possible that the same environmental processes that happen in clusters are also happening in filaments. This would have an impact on the evolution of infalling galaxies before they even become members of the cluster. The primary goals of this study are to develop selection criteria that will identify filaments in the region around the Virgo cluster, and to analyze the star formation properties and gas content in the galaxies identified to be in filaments.

Research literature - add references. (Koopmann 2004) (Kim 2016)

## Catalogs

### WISE

describe how WISE measures magnitudes - how to convert them to AB magnitudes.

we convert the WISE Vega magnitudes to AB magnitudes according to the conversion given on WISE website11http://wise2.ipac.caltech.edu/docs/release/allsky/expsup/sec4_4h.html#conv2ab.

$$m_{AB}=m_{Vega}+6.620\\$$

how to convert WISE 22$$\mu m$$  fluxes to infrared star-formation rates?

• We have AB magnitudes(add 6.6 to WISE model magnitudes-see code)

• Find AB flux zero point (Should be one for every filter)

• convert magnitudes to flux ($$\mu Jy$$)

• feed flux and z into chary_elbaz_24um.py

look into unWISE magnitudes. how do we get magnitudes for a whole list of galaxies?

### Bulge$$+$$Disk Models

• Simard1toNSA.fits: N=4 at center of galaxy

• Simard2toNSA.fits: N is a free parameter at center of galaxy

• Simard3toNSA.fits: pure sersic profile