This photograph of the nearest Seyfert galaxy, NGC 4395, was taken with the Palomar 200-inch telescope. NGC 4395 is the least luminous and nearest Seyfert galaxy known, located eight million light-years away in the direction of the constellation Canes Venatici (The Hunting Dogs). A Seyfert galaxy is a class of nearby galaxy that has an extremely bright central region that often obscure the much dimmer stars in the surrounding disk. The nucleus gives off prodigious amounts of energy largely in the form of high-energy x-rays and gamma rays. Spectroscopic observations made with NASA's Hubble Space Telescope (HST) further support the theory that this galaxy and other active galaxies are fueled by a massive black hole at the center. Most astronomers believe that the only object capable of producing such tremendous amounts of energy in a relatively small galactic core is a black hole. The HST results rule out vigorous star formation as the alternative explanation for the power source at the heart of Seyferts. HST did not detect any absorption lines that would he produced by stars in the nucleus, therefore stellar processes are not responsible for light emitted by the nucleus. HST data also show that the galaxy's center is no more than two light-years across - less than half the distance from our Sun to the nearest star. The findings are reported in the June 20, 1993 issue of The Astrophysical Journal by Filippenko, graduate student Luis C. Ho, and California Institute of Technology astronomer Wallace L.W. Sargent.
Credits
Photo Credit: Allan Sandage, Carnegie Institution| About The Object | |
|---|---|
| Object Name | NGC 4395 |
| R.A. Position | 12h 25m 48.92s |
| Dec. Position | 33° 32' 47.79" |
| 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 |
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| 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. |
