Fig.1: 2' by 2' simulation (consisting of 16 pieces)

This is a simulated image of the James Webb Space Telescope (JWST) deep field. Field of view of this image (2' by 2') is comparable to that of the Hubble Deep Field (HDF), yet this represents only one quarter of the proposed field of view (4' by 4') of the NGST.

Total exposure time is assumed to be 30 hours (about one tenth of the time spent for the HDF observation), and the location of the telescope is assumed to be at 1 AU from the Sun.

There are nearly 15000 galaxies in this image which is more than 5 times as many as the number of galaxies in the HDF.

Red color represents observation in K broadband filter (2 micron), green color is for observation in J broadband filter (1.2 micron), and blue color is for observation in I broadband filter (0.8 micron) in this false color image. (Myungshin Im, STScI)

Fig.2: 30" by 30" simulation with redshift

Redshifts are indicated for galaxies in a small portion of the field presented in Fig.1 (the lower left corner). The field of view is 30" by 30".

Try find small faint red or green objects. They are galaxies at very high redshifts (z > 7), meaning that they are the first galaxies to form out of the dark age of the universe which starts shortly after the Big Bang and lasts for about a few hundred million years.

Intergalactic absorption of the light below the rest frame wavelengths of 912 - 1216 Angstroms causes no detection of high redshift objects at optical and short near infrared wavelengths in observer's frame (I-band or J-band). Thus, high redshift objects can be recognized as I-band dropouts (z > 7, yellow objects) and J-band dropouts (z > 10, red objects).

Detection of objects at this distance thus far has not been accomplished either from the ground nor from the space. (Myungshin Im, STScI)

Fig.3: 30" by 30" simulation with redshift (ground-based)

Postscript file of poster presented at the 191st AAS meeting, Washinton D.C., Jan. 6-10, 1998

Images for NGST meeting in Europe

GIF files of NGST simulations in three different stretches
poster1.gif
poster2.gif
poster3.gif

NGST simulation with redshift identification

Myungshin Im