1. Do LIRGs follow the Tully-Fisher relation?
Verónica Torres Martínez and Adriana J. Colón Rosa
Dra. Tapasi Ghosh, Arecibo Observatory and San Felipe College, Arecibo, Puerto Rico
Do LIRGs follow the Tully-Fisher relation?
Abstract
Objectives
Conclusion
We conclude that our hypothesis will be supported as long as the LIRGs have the rotation and mass distribution of a normal galaxy. If the LIRGs does not follows those two requirements  the Tully-Fisher relation will not work and our hypothesis will not be supported.
The purpose of this research is to study the LIRGs (Luminous Infrared Galaxies) and see if they follow the Tully-Fisher relation. The LIRGs are different to normal galaxies for the fact that they emit 90% of their light in infrared. The Tully-Fisher relation states that the bigger the galaxy is, the faster it rotates. The faster the galaxy rotates, the wider is the emission line in velocity. Also, the bigger the galaxy, the more is its luminosity. Tully-Fisher relation shows that for normal galaxies, the velocity width (W) of the lines is proportional to its luminosity (L) following an equation, L ∝ W . In a sample of 33 LIRGs we are measuring the neutral hydrogen emission line width. We will find the luminosities of these galaxies from literature and study if the Tully-Fisher law is maintained by the LIRGs. This will indicate whether the LIRGs are peculiar either in their motion or in the amount of light they emit.
When two different galaxies collide takes time to have a normal rotation and a well distribution of mass. There are other galaxies that have been long time rotating  to each other and have similar characteristics. Since they are related and have a common rotation it wouldn’t take too long to normalize.
The main objective is get to know what are the LIRGs , the Tully-Fisher relation and their properties.  The objective of the research is to reveal if the Tully-Fisher relation function , in spite of normal galaxies, can be applied to LIRGs. i
Methods and Materials
Future Work
Once we’ve done this research of the LIRGs and Tully-Fisher relation we will continue studying them. When we have close galaxies we can study them with facility. But, when they are far, it becomes harder because of the distance. We want to know if the Tully Fisher relation works for LIRGs that are far from us and for what more we can apply this relation.
To perform this investigation we needed  knowledge about the subject, so we did a research in depth about galaxies, the Tully-Fisher relation, LIRGs, , and to have more security people we met with professionals who are dedicated to working with the subject. As is Professor Naphtali Sotero Rivera Castillo, of the University of Puerto Rico at Arecibo and our mentor Dr. T. Ghosh, they provided us totally reliable sources such as articles and information materials to the professional level, books, web links and the great knowledge they have about it. By having all these materials and all information collected from different research we did, where we could increase knowledge, we could develop a hypothesis, conducting an investigation, results and a conclusion.
Introduction
Galaxy: is a large system of stars, star clusters, gas, dust, and nebulae orbiting a common center of mass.
LIRGs (Luminous Infrared Galaxies): These galaxies are very bright in IR (Infrared). LIRGs are the result of mix or collisions of galaxies. The 90% of the light they emit is IR. LIRGs are not common galactic bodies, their luminosity is changing constantly, and they generate approximately 100
new stars per year.
IR (Infrared) : The portion of the electromagnetic spectrum with wavelengths longer than red light, ranging from 700 nm to about 1 mm, between visible light and radio waves.
Tully-Fisher Relation: Brent Tully and J. Richard Fisher are two astronomers that together, they proposed the Tully-Fisher relation. The Tully-Fisher relation states that if we know the rotation velocity of the galaxy we can determine how bright she is. With this relation we can find its distance by comparing the magnitude between the brightness. Tully-Fisher relation applies to galaxies with a normal rotation and a good mass distribution.
References
GUZMAN, R., Class Notes, web site, Ch15.html , 05-Jan-2009
FREEMAN, K., Structure and Dynamics in the Local Universe, web site, Dark Matter and Tully-Fisher Law,
NEHONSKY, F., Distance measurement in space, web site, Tully-Fisher Relation, /99
Seeds, M. and Backman, D. (2010/11) Galaxies, Astro, ( pp ),(Instructor’s Edition), Boston, MA, USA : Laura Rush, B-books, Ltd.
Robert, M. S. & Haynes .M.P. ,1994 Annu. Rev. Astron. Astrophys., 32: 115
Haynes, M.P. & Giovanelly , R. Astron.J. 1984, 89, 758
Results
Acknowledgements
Special thank to:
Dra. Tapasi Ghosh
Prof. Neftalí Sotero Rivera Castillo
Arecibo Observatory
Dr. Juan Arratia
Luis Font
Aida Albó
NSF
Jenipher D. González
Carlos E. Caro