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  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  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 criteria  Needed to be outside of the Milky Way’s disk of dust  Could 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 formation  Faint quasars  White 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 Fornax  Also looks back into time: 13 billion years  Evidence for Big Bang, and finite age of universe  Contains perhaps as many as 10,000 galaxies

Works Cited  Deep_Field  Space_Telescope  7/hdf-key-findings.html