Details of a simulated image of the Andromeda galaxy highlight the high resolution of WFIRST imagery. Unlike a typical wide field camera, which can cover a large area of sky but cannot reveal fine details, WFIRST will provide both a large field of view and high resolution. The details shown here each cover about 0.0013 square degrees of sky, the equivalent to a single infrared image from Hubble’s WFC3 camera. The pixel scale is 0.11 arcseconds/pixel.
The pull-out detail on the left shows the diversity of populations in the disk. The bright blue stars are young, recently formed hot populations that tend to be in association, while the red stars are the old stars that are well-mixed throughout the disk.
The middle pull-out shows a thick cloud of dust in the disk. Near the center of the detail, the dust is thick enough that there are noticeably fewer stars detected, even in the near infrared, which penetrates more dust than optical light.
The right pull-out shows another mix of populations, but this time the young blue stars are spread along a relatively linear structure. There is also an example of a background galaxy in the lower middle portion of the image.
This simulated image was made using high-resolution near-infrared data collected by Hubble for the Panchromatic Hubble Andromeda Treasury (PHAT) program. Researchers used the PHAT imagery to compile a catalog of stars in the field of view. The color and brightness data were then fed into a computer program that models the corresponding output from WFIRST, based on the design of the telescope and its instruments.
The region of Andromeda covered by the PHAT mosaic is outlined in teal. The black regions within some of the detector squares are gaps in the PHAT data. In an actual WFIRST image of Andromeda, each square would be completely filled with near-infrared light from the stars, gas, and dust of the galaxy.
The black space between the white outlines represents chip gaps: areas between detectors where data are not recorded. When WFIRST is operating, these gaps can be filled by moving the telescope slightly and combining exposures.
One notable difference between WFIRST and Hubble is wavelength range: the colors they can detect. While Hubble covers the full spectrum of visible light, along with near ultraviolet and near infrared, WFIRST is limited to the near infrared and the red end of the visible spectrum. The colors used in this image are not the colors that our eyes would see: blue represents visible red light (0.62 microns); green represents very near infrared light (1.06 microns); and red represents near-infrared light (1.58 microns).
Credits
NASA, STScI, and B. F. Williams (University of Washington)| About The Object | |
|---|---|
| Object Name | M31, Andromeda Galaxy, NGC 224 |
| Object Description | Spiral Galaxy |
| R.A. Position | 00:42 |
| Dec. Position | +41:15 |
| Constellation | Andromeda |
| Distance | 2.5 million light-years |
| About The Data | |
| Data Description | Simulated WFIRST data generated using the Space Telescope Image Product Simulator (STIPS), based on near-infrared Hubble data from the PHAT program. |
| Instrument | WFIRST Wide Field Instrument (Simulated) |
| About The Image | |
| Color Info | This image is a composite of simulated data from three separate filters on the Wide Field Instrument on the Wide Field Infrared Survey Telescope. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: • Blue: R062 (visible red light; 0.62 microns) • Green: Y106 (near-infrared light; 1.06 microns) • Red: H158 (near-infrared light; 1.58 microns) |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
