Hubble Deep Field

Daniel Hazard

Background

The Hubble Deep Field (HDF) is a composite picture of 342 different images.

The HDF covers an area of 144 arc seconds.Taken by the Hubble Space Telescope (HST)

over a period of 10 consecutive days in December of 1995.

Taken by the Wide Field and Planetary Camera 2.

Total exposure time was more than 100 hours.

… the telescope and its origins

Astronomer Lyman Spitzer calls for space-based observatory in 1946; designing of HST begun in 1978; launched in 1990.

NASA and ESA funded, NASA built.

Named after astronomer Edwin Hubble.

Total costs to date have been estimated to be close to $14,000,000,000.

May be replaced by James Webb Space Telescope in 2013.

Selecting the HDF

HDF is but a tiny, tiny portion of the sky seen in the Northern Hemisphere; more specifically: a small section which lies within the Ursa Major constellation.

Field was selected by the following criteriaNeeded to be outside of the Milky Way’s disk

of dustCould not contain very bright objects or

anything that emitted too much infrared, x-ray, or UV

In addition, field could never be occulted by the Earth or Moon.

… HDF within the sky

Describing the HDF

As a result of the field’s size, it is thought to display less than 10 stars from our galaxy.

Most of the objects seen are distant galaxies--nearly 3,000 of them.

There are also a number of bluish objects and regions. They might be:Regions of intense star formationFaint quasarsWhite dwarfs

Initial implications of HDF

HDF looks into space, and, in effect, back in time Large number of galaxies with unforeseen

redshift values; prior to the HDF no galaxies with a redshift value higher than 1

Helped in debate over the missing mass of the universe. Prior to the HDF there were theories of faint yet massive objects in the outer regions of galaxies such as red dwarves and planets making up this missing, non visible mass. The HDF proved that this wasn’t the case, as these proposed faint objects did not exist. Thus, the mass must exist in other non visible forms such as dark matter and dark energy.

A second HDF

Named Hubble Deep Field South (HDF-S); very similar to original HDF, now named Hubble Deep Field North (HDF-North).

Same criteria, only now in Southern Hemisphere, within the Tucana constellation.

Taken over in 1998 over 10 days.

Content of HDF-S

Remarkably similar to HDF-N.

One major difference is the existence of a known quasar.

Implications of HDF-S

In general, HDF-S confirmed many findings of HDF-N.

Evidence for cosmological principle: correlations between HDF-N and HDF-S help support the idea that the universe is homogenous and isotropic.

… one more image

Hubble Ultra Deep Field (HUDF) is appropriately titled: taken over a period of several months in 2003 and 2004, the HUDF is the deepest image ever taken in visible light.

Taken within the constellation of FornaxAlso looks back into time: 13 billion yearsEvidence for Big Bang, and finite age of

universeContains perhaps as many as 10,000

galaxies

Works Cited

http://en.wikipedia.org/wiki/Hubble_Deep_Field

http://en.wikipedia.org/wiki/Hubble_Space_Telescope

http://oposite.stsci.edu/pubinfo/PR/97/hdf-key-findings.html