Kevin Cooke

Galaxy Characteristics and Importance

Sloan Digital Sky Survey: What is it?

IRAF: Uses and advantages/disadvantages◦ Fits files?

Question: Can we observe the red sequence from the cluster total redness? What are the observed features of SDSSJ1336?

M89Hubble Space Telescope

Lack of cold dust in low redshift ellipticals◦ This manifests in low star formation.

Redness, defined here as the difference between blue and red, should increase with z.

Little to no ionization emission lines due to lack of ionizing radiation.

8 year project from 4000-10000 A◦ 8400 square degrees covered

Includes over 930,000 Galaxies!◦ > 120,000 quasars

More than a quarter of the sky and capable of measuring redshift.◦ 3D Universe generation possible!

Apache Point Observatory, Sunspot, NM◦ Maintained by New Mexico State University

Dedicated 2.5 m telescope. 120 megapixels

5 filters◦ u - 3543 A◦ g - 4770 A◦ r - 6231 A◦ i - 7625 A◦ z - 9134 A

Total of 3 surveys performed since 2000.◦ SDSS I 2000-2005◦ SDSS II 2005-2008◦ SDSS III 2008-2014

The SDSS was funded by the Alfred P. Sloan Foundation, NSF, and the Department of Energy.

Organized by the National Optical Astronomy Observatory (NOAO)

A collection of tasks using Unix architecture rather than one program.

No error or exception feedback, the impetus for PyRAF.

A fits file is an image storage file extension first developed in the 1980s. Support office available at NASA GSFC.

Stores data as a table of values in multiple ‘dimensions’ that can be called individually.

This allows for multiple wavelength files to be in one file together (Hopefully properly labeled)

A measurement of the redness of the population of ellipticals in clusters. Done by Mike Gladders and H.K.C. Yee at the University of Toronto.

Can we observe the trend purely based on a photometrically derived redness for the entire cluster?◦ Could be a rough estimation device.

Gladders, M., & Yee, H. (2000). A new method for galaxy cluster detection.

Clusters have differentiation of each galaxy type at each redshift.

Each color-color relation can be plotted alongside.

Important -Ellipticals do not overlap!

A redward trend is visible at low confidence.

Caveat: Total color, not individual color.

More data is needed.

The modeled color-color plot of galaxy clusters was for a apparent magnitude of -22.

Projection effects from incorrect masking during photometry in the pipeline.

Filter wavelengths may not have the same coverage.

Attain data on constituents of cluster.

Test for layering of ellipticals, spirals, etc.

Develop alternative analytical methods.◦ IDL◦ QfitsView

Focus on a few important galaxies, or at least that have easily read data…

Brightest Cluster Galaxy◦ Dominant elliptical at the center of a cluster.◦ Lensing?

Z = 0.1764◦ This translates to 2.1 Gyr ago.◦ Redshift applies to all colors.

SDSSJ1336 has detectable OIII, Hβ◦ OIII/Hβ=0.46

SDSSJ1336 is a LINER Galaxy.

The Red Sequence may be visible with average color, however high margin for error.

Many display tools are available for data,and future work should focus on this possibilities.

SDSS Visual Spectra Interactive Display

IRAF

Gladders, M., & Yee, H. (2000). A New Method for Galaxy Cluster Detection.