241123 - M74 "Phantom" galaxy
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click image to enlarge
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ASTRO:
type=Grand Design Spiral Galaxy const=Pisces mag=9.4 dist=32 M ly size=~95 k ly IMAGE: location=EB Driveway BrtlCls=4 exposure=CMOS OSC: 335x120s (11.2h) EQUIPMENT: camera=ZWO ASI2600MC-Pro optics=Explore Scientific ED102 CF corrector=Baader Hyperion 24mm EP (proj. mode), FL(eff.)=1238mm, f/12.1 filter=Optolong L-Pro LPS mount=Celestron AVX EQ guiding=Orion 60x240mm, ZWO ASI224MC SOFTWARE: acquisition=Stellarium, APT, PHD2 processing=PixInsight (RCAstro) (Seti-Astro), Photoshop (APF-R) (Lumenzia), LrC |
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Resembling festive lights on a holiday wreath, this image of the nearby spiral galaxy M74 is an iconic reminder of the Christmas season. Also indicative of the holidays is the fact that M74's achronycal rise (i.e. - its earliest visible rise in the east after sunset) falls each year in the late-November to early December time-frame (depending on obstructions near the horizon). Bright knots of glowing gas and lit-up spiral arms become fully visible right around Christmas time, indicating a rich environment of star formation.
This so-called "Phantom" galaxy is also known as Messier 74 (M74 for short), and NGC 628. It is called the "Phantom" because it’s surface brightness is low, and so tends to slip in-and-out of visibility to the naked eye. It is a stunning example of a "grand-design" spiral galaxy that is viewed from Earth in a directly face-on orientation. Its symmetrical spiral arms emanate from the galaxy's central nucleus and are dotted with clusters of young blue stars and hot, glowing pink regions of ionized hydrogen. These regions of star formation show an excess of light at ultraviolet wavelengths. Also tracing along the spiral arms are winding dust lanes that begin very near the nucleus and follow along the length of the spiral arms.
M74 is located roughly 32 million light-years away in the direction of the constellation Pisces, the Fish, and appx 1.5° east-northeast of star Eta Piscium. It is the dominant member of a small group of a half dozen galaxies known as the M74 galaxy group. It is estimated that M74 is home to about 100 billion stars, making it slightly smaller than our Milky Way.
The Phantom was first discovered by French astronomer Pierre Méchain in 1780. Then just a few weeks later it was added to Charles Messier's famous catalog of deep-sky objects.
In 2005 the Chandra X-ray Observatory announced M74 contains an ultraluminous X-ray source (ULX) that is radiating more powerful X-rays than a neutron star. The emissions are varying in periodic intervals of around two hours. The source has an estimated mass of about 10,000 Suns like ours. This indicates it is an intermediate-mass black hole, which is a rather uncommon classification to be present in a galaxy, being in between the size of stellar black holes and the massive black holes theorized to be at the center of most other galaxies. Such objects are normally associated with smaller ("stellar") black holes that form within star clusters.
For observers, this particular galaxy has the second-lowest surface brightness (as seen from Earth) of any Messier object. (M101 has the lowest.) It requires extremely good night viewing conditions to be seen with a moderately powered telescope or binoculars. In fact, it is best viewed using low magnification; because when highly magnified, the diffuse emission becomes more extended and appears too faint to be seen by many people (...thus lending credence to its "phantom" designation). M74 is most easily seen using averted vision when one's eyes are fully dark adapted. For imagers, like most galaxies in the night sky this one's spectral pattern of emitted light makes it a broad-band target. That is, the colors contained in its light emissions fall along almost the entire visible spectrum of natural, white light. The photographic filter used to create color images like this one is a broad-band, light pollution suppression ("LPS") filter. When placed in front of a camera sensor, it is designed to block specific wavelengths of light emitted from typical man-made sources like mercury vapor and high-pressure sodium street and commercial lights, while at the same time allowing the more natural wavelengths in the remaining parts of the visible spectrum to pass through to the camera sensor.
This so-called "Phantom" galaxy is also known as Messier 74 (M74 for short), and NGC 628. It is called the "Phantom" because it’s surface brightness is low, and so tends to slip in-and-out of visibility to the naked eye. It is a stunning example of a "grand-design" spiral galaxy that is viewed from Earth in a directly face-on orientation. Its symmetrical spiral arms emanate from the galaxy's central nucleus and are dotted with clusters of young blue stars and hot, glowing pink regions of ionized hydrogen. These regions of star formation show an excess of light at ultraviolet wavelengths. Also tracing along the spiral arms are winding dust lanes that begin very near the nucleus and follow along the length of the spiral arms.
M74 is located roughly 32 million light-years away in the direction of the constellation Pisces, the Fish, and appx 1.5° east-northeast of star Eta Piscium. It is the dominant member of a small group of a half dozen galaxies known as the M74 galaxy group. It is estimated that M74 is home to about 100 billion stars, making it slightly smaller than our Milky Way.
The Phantom was first discovered by French astronomer Pierre Méchain in 1780. Then just a few weeks later it was added to Charles Messier's famous catalog of deep-sky objects.
In 2005 the Chandra X-ray Observatory announced M74 contains an ultraluminous X-ray source (ULX) that is radiating more powerful X-rays than a neutron star. The emissions are varying in periodic intervals of around two hours. The source has an estimated mass of about 10,000 Suns like ours. This indicates it is an intermediate-mass black hole, which is a rather uncommon classification to be present in a galaxy, being in between the size of stellar black holes and the massive black holes theorized to be at the center of most other galaxies. Such objects are normally associated with smaller ("stellar") black holes that form within star clusters.
For observers, this particular galaxy has the second-lowest surface brightness (as seen from Earth) of any Messier object. (M101 has the lowest.) It requires extremely good night viewing conditions to be seen with a moderately powered telescope or binoculars. In fact, it is best viewed using low magnification; because when highly magnified, the diffuse emission becomes more extended and appears too faint to be seen by many people (...thus lending credence to its "phantom" designation). M74 is most easily seen using averted vision when one's eyes are fully dark adapted. For imagers, like most galaxies in the night sky this one's spectral pattern of emitted light makes it a broad-band target. That is, the colors contained in its light emissions fall along almost the entire visible spectrum of natural, white light. The photographic filter used to create color images like this one is a broad-band, light pollution suppression ("LPS") filter. When placed in front of a camera sensor, it is designed to block specific wavelengths of light emitted from typical man-made sources like mercury vapor and high-pressure sodium street and commercial lights, while at the same time allowing the more natural wavelengths in the remaining parts of the visible spectrum to pass through to the camera sensor.