# Intergalactic medium/Laboratory

This laboratory is an activity for you to explore the universe for an intergalactic medium. While it is part of the astronomy course principles of radiation astronomy, it is also independent.
Some suggested intergalactic medium entities to consider are star clusters, stellar distributions, electromagnetic radiation, neutrinos, mass, time, Euclidean space, Non-Euclidean space, dust clouds, and spacetime.
More importantly, there are your intergalactic medium entities.
You may choose to define your intergalactic medium entities or use those already available.
Usually, research follows someone else's ideas of how to do something. But, in this laboratory you can create these too.
Okay, this is an astronomy intergalactic medium laboratory, but you may create what an intergalactic medium is.
Yes, this laboratory is structured.
I will provide an example of an intergalactic medium. The rest is up to you.
Questions, if any, are best placed on the discussion page.

## Control groups

For exploring an intergalactic medium, what would make an acceptable control group? Think about a control group to compare your intergalactic medium or your process of exploring for one to.

## Interaction degree

In the lecture intergalactic medium, interacting galaxies are introduced. For my example, I will attempt to evaluate the degree of interaction of the two galaxies in the image at the top of this resource. If you want to evaluate a pair of interacting galaxies, here is a fairly current list from the category at Wikimedia Commons: interacting galaxies.

## Introduction

"UGC 9618, also known as VV 340 or Arp 302 consists of a pair of very gas-rich spiral galaxies in their early stages of interaction: VV 340A is seen edge-on to the left, and VV 340B face-on to the right. An enormous amount of infrared light is radiated by the gas from massive stars that are forming at a rate similar to the most vigorous giant star-forming regions in our own Milky Way. UGC 9618 is 450 million light-years away from Earth, and is the 302nd galaxy in Arp's Atlas of Peculiar Galaxies." The image was taken through the Hubble Space Telescope F435W (B) and F814W (I) filters for 33 min of exposure. The estimated distance is 450 million light-years.

## Experiments

The coordinates for UGC 9618 are 14$^h$ 57$^m$ 00.4$^s$ +24° 36' 44" at the center of the cross hairs.
According to SIMBAD VV340A is the face-on galaxy, and VV340B is the edge-on galaxy.
In both images of UGC 9618, 50 mm corresponds to 2.4' of arc. The galaxy on edge is 16 mm in length, while the other is closer to 12 mm. At 4.5 x 10$^8$ lyrs, VV340B (edge-on) is about 1.01 x 10$^5$ lyrs in diameter, while VV340A (face-on) is about 7.55 x 10$^4$ lyrs in diameter.
VV340A (SIMBAD) appears to be Hubble sequence Sa type galaxy, with VV340B (SIMBAD) may be similar. VV340A (SIMBAD) is a right-handed spiral, with its axis pointed out of the paper plane toward the viewer (face-on).
VV340A (SIMBAD) has its center closer to the point between the two (4 mm) than to the opposing edge (8 mm) suggesting that its spiral arms on the side closest to VV340B (SIMBAD) are missing or compressed by about 50 % compared to the opposing side. This suggests that VV340A (SIMBAD) has loss less than 33 % of its luminous sources either to VV340B (SIMBAD), to the interaction between them, or to compression in the direction of VV340A (SIMBAD).
VV340B (SIMBAD) appears to have its center at 7 mm from the interaction volume whereas the other side away from the interaction is about 9 mm in width. This suggests only about 13 % or less of VV340B (SIMBAD) has been lost to the interaction, VV340A (SIMBAD), or compression.
The bright luminous source in the interaction volume may be a foreground star or a supernova in the interaction volume.
Additional images of UGC 9618 are available at NED: Images and maps in NED archive for object UGC 09618.
If the interaction is endothermic (absorbs energy), then luminous sources in or near the interaction volume may be no longer visually luminous (stars may have gone out).
If the interaction is exothermic (gives off energy), then the apparently missing luminous sources may now be radiating in the ultraviolet or shorter wavelengths such as X-rays.
Neither SIMBAD nor NED shows either galaxy as an X-ray source, but both are infrared sources.
The image at right shows VV340B (SIMBAD), the northern (N) galaxy as a major source of X-rays (purple). VV340A (SIMBAD), the southern galaxy (S), is in red, green, and blue.
In the second image at right, the northern galaxy VV340B is primarily an infrared image, whereas VV340A is primarily an ultraviolet image.

## Results

The lack of high energy output from the interaction volume suggests that any loss of luminous sources from either galaxy is not exothermic. The lack of equal or excessive endothermic energy suggests that luminous sources are not being lost due to interaction. The asymmetry in both galaxies may indicate a common origin originally between them. Both galaxies have removed luminous sources from the interaction volume.

## Discussion

The visual/optical image at the top of this resource shows the edge-on galaxy as yellow to orange in color with prominent dust lanes. The face-on galaxy seems more bluish suggesting younger stars.
Both the X-ray image and the optical/visual image suggest that the edge-on galaxy is closer to a Hubble type S0 than any other type.
The lack of luminous sources between the galaxies in the interaction volume does not suggest that these galaxies are merging.
The asymmetry in both galaxies, primarily toward the interaction volume, may indicate a common origin originally between them. Both galaxies have removed luminous sources from the interaction volume and may be actually moving apart from their common and competitive origin.
The asymmetry of both galaxies roughly centered on the interaction volume argues against these two galaxies being double galaxies (one nearer than the other, but not interacting) rather than interacting galaxies.

## Conclusions

The pair of galaxies that compose UGC 9618 appear to be interacting rather than a mere galaxy double. The lack of luminous sources at any wavelength in the interaction volume suggests that both galaxies have cleaned out nearly all luminous sources from the interaction volume. The asymmetry being approximately centered on the interaction volume together with the lack of luminous sources within this volume suggests that the two galaxies are not merging but separating.

## Report

Title
The degree of interaction in the UGC 9618 galaxy system
by --Marshallsumter (discuss • contribs) 23:14, 15 February 2014 (UTC)
Abstract
The pair of galaxies that compose UGC 9618 are analyzed with respect to their degree of interaction. VV340A appears to be less than 33 % involved in the interaction, while VV340B is less than or about 13 % involved. The distribution and radiation types of luminous sources suggests that the two galaxies are separating or at least not merging from a possible common origin.
Introduction
Current opinion is that VV340A and VV340B are in the early stages of merging. "An enormous amount of infrared light [from VV340B] is radiated by the gas from massive stars that are forming at a rate similar to the most vigorous giant star-forming regions in our own Milky Way."
Experiment
Measurements are made of the approximate distribution of luminous sources in both galaxies. Images of UGC 9618 from various radiation astronomies are checked for information regarding either galaxy. Scans of these galaxies are available from microwave astronomy through X-ray astronomy.
Results
SIMBAD does not report the bright luminous source apparently in the interaction volume as a supernova so it is likely a foreground star or a star cluster remnant in the interaction volume. Orange and yellow astronomy reveal that the edge-on galaxy may be composed of older or cooler stars. The prevalence of blue (from blue astronomy) in the face-on galaxy suggests younger or hotter stars visually. Ultraviolet astronomy of the face-on galaxy also suggests hotter or younger stars. Somewhat surprising is the enormous amount of X-rays from the edge-on galaxy. Usually, ultraviolet, X-rays and gamma-rays are associated with very hot sources.
Measurements of the distribution of luminous sources suggest that an asymmetry in both galaxies exists toward and with respect to the interaction volume.
With the exception of the one very bright source on the edge of the interaction volume, no luminous sources of any kind exist between the two galaxies in the interaction volume.
Discussion
The infrared portion of the composite image with ultraviolet strongly suggests that the edge-on galaxy is much cooler in general than the face-on galaxy.
The large X-ray output surrounding primarily the more central portion of the edge-on galaxy suggests a very high temperature galactic coronal cloud. X-rays are detected from both galaxies though mostly only from the inner core region of the face-on galaxy much like the Milky Way.
The lack of luminous sources between the galaxies in the interaction volume suggests that these galaxies are not merging.
The asymmetry in both galaxies, primarily toward the interaction volume, may indicate a common origin originally between them. Both galaxies have removed luminous sources from the interaction volume and may be actually moving apart from their common and competitive origin.
The asymmetry of both galaxies roughly centered on the interaction volume argues against these two galaxies being double galaxies (one nearer than the other, but not interacting) rather than interacting galaxies.
Conclusion
The pair of galaxies that compose UGC 9618 appear to be interacting rather than a mere galaxy double. The lack of luminous sources at any wavelength in the interaction volume suggests that both galaxies have cleaned out nearly all luminous sources from the interaction volume. The asymmetry being approximately centered on the interaction volume together with the lack of luminous sources within this volume suggests that the two galaxies are not merging but separating.

## Evaluation

To assess your intergalactic medium, including your justification, analysis and discussion, I will provide such an assessment of my example for comparison.
Evaluation
Although many radiation astronomy images of the galaxy pair UGC 9618 have been consulted, the overall conclusion that these two galaxies are not merging is in direct disagreement with several primary sources. These sources need to be consulted and examined to obtain a more thorough understanding of this galaxy system.

## Hypotheses

* The speed of electromagnetic radiation through the intergalactic medium is probably more of a velocity.