1. The open cluster ngc 7129
Joshua thomas

2. Overview Intro to the reflection nebula NGC 7129 Facts and Images
GAO Data
Stellar Formation in NGC 7129
Spitzer Analysis

3. NGc 7129 Open cluster in the constellation of Cepheus
Large molecular cloud and area of dense star formation
Contains multiple herbig haro objects or star formation jets
RA/Dec: 21h 42m 56s / ’ 12”
Image Courtesy: T. A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF

4. Pretty pictures
Image Courtesy NASA/JPL-Caltech/T. Megeath (Harvard-Smithsonian CfA)
Image courtesy Leonardi Orazi ( )

5. Fun facts and images
Has been described as “singularly unimpressive” as a “small group of half a dozen dim stars” (R. Thompson & B. Thompson, 171)2
Contains 3 herbig-haro objects which are emitting large jets of gas into the cloud
Contains 47 young stellar objects as identified by B. Stolzer & A. Scholz1
Left: 2MASS survey J band. Right: WISE 3.4 micron surevey

6. Our data
Observations of the cluster NGC 7129 conducted on January 21, 2016, 19:50-20:20 CST at the Glenlea Astronomical Observatory
Basic greyscale processed image of NGC 7129 from GAO

7. Observation conditions
Seeing was a bit below average
Although cloud cover was at a minimum, the moon was nearly full and very bright
SQM read a quality of when observations started
Throughout the observations the light level fluctuated significantly likely due to the moonlight

8. Typical dark sky flat from GAO
Our dark sky master flat from GAO

9. Image processing There were a few issues with our raw data
Primarily that of the dark sky flat shown previously
Even the actual science images contained highly varying brightness levels
We also had to omit a few frames of the raw data set (frames 29, 38, 39) which were found to be blurry or unacceptable
Image at end of night
Image at beginning of night

10. Top row: Our own processed images in greyscale, and other color lookup tables
Bottom row: Processed spitzer 3.6 micron IRAC data in greyscale and color scheme

11. Research background
In the optical spectrum the cluster is generally unimpressive
Only in the X-ray and IR spectrum does it become more interesting
It is through an examination of these wavelengths that NGC 7129 was found to be a region of dense star formation with many young forming stars
Herbig-Haro object Image courtesy J. Morse/STSci and NASA

12. Stellar formation
Star formation begins when an interstellar cloud begins to collapse due to gravity
The point to which the gas converges becomes extremely hot as a result
Eventually this can turn into the beginnings of a star or ‘protostar’
This results in a dense protostar core surrounded by a swirling cloud of hot gas
It is this abundance of hot gas that causes the stars spectrum to shift more toward the infrared

13. Protostar detection
This excess dust and gas causes the star to emit more so in the infrared spectrum then other main sequence stars
The forming star will emit more infrared radiation then would be expected from just a black body radiator
This is known extra radiation from the surrounding dust is known as ‘infrared excess’

14. Protostars in ngc 7129
When the Spitzer telescope made its observations of the cluster it found strong infrared emissions
This was then further analyzed by B. Stelzer and A. Scholz in their article “A Chandra and Spitzer census of the young star cluster in the reflection nebula NGC 7129”1
By means of a “color-color” graph Stelzer & Scholz (2009) were able determine a large quantity of YSO’s in the cluster. They were even able to classify these into two different types

15. Radio Spectroscopy
For the Spitzer data analysis Stelzer and Scholz (2009) made use of 4 different wavelengths observed by the Infrared Array Camera (IRAC).
This included observations in 3.6, 4.5, 5.8 and 8.0 microns
The comparison of magnitude to observed wavelength is a color-color graph

16. Color-color graphs
Image from B. Stelzer & A. Scholz (2009)1

17. Focus area: Spitzer analysis
The spritzer IRAC survey raw data is in the form of many 5.2’ x 5.2’ field of view images
In order to properly analyze the data these must be combined in a mosaic
It is with a combination of all 4 wavelength mosaic images that analysis can be performed
In order to create the image to the right I made use of the program ‘Montage’ which compiles and arranges image sets
Spitzer 4.5 micron raw frame

18. colorizing
Each wavelength image can then be assigned a color either arbitrarily or based upon the radiation energy
The combination of these frames is then the composite color image
For my project I did this combination in multiple different color combinations and programs as shown

19. Composite examples Colored spritzer data with
Red = 8.0 μm Yellow = 6.8 μm
Green = 4.5 μm Blue = 3.5 μm
Colored Spitzer data with
Red = 8.0 μm, Green = 4.5 μm
Blue = 3.5 μm

20. Spitzer and 2MASS data with the 2MASS J Band in blue and Spitzer 8
Spitzer and 2MASS data with the 2MASS J Band in blue and Spitzer 8.0micron in red
Combination of all 3 2MASS images and 4 Spitzer with red being the highest wavelength and blue the smallest

21. Sources
1Scholz A, Stelzer B A Chandra and Spitzer census of the young star cluster in the reflection nebula NGC A&A. 507(1):227-40
IRAC Instrument and Support Team IRAC Instrument Handbook.
Allen LE, Fazio GG, Gutermuth RA, Megeath ST, Myers PC, Pipher JL A Spitzer Survey of Young Stellar Clusters within one Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis. ApJS. 184:18-83.
Eiroa C, Gomez de Castro AI, Miranda LF New Herbi-Haro objects and pre-main sequence stars in the star formation region of NGC A&A. 271:
2Thompson RB, Thompson BF Cepheus: The King. Illustrated Guide to Astronomical Wonders. Jepson B. pp 171.
NASA Science Astrophysics Stars. stars-form-and-evolve/