NGC 4565 (also known as the Needle Galaxy or Caldwell 38) is an edge-on

spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Coma Berenices Coma Berenices is an ancient asterism in the northern sky, which has been defined as one of the 88 modern constellations. It is in the direction of the fourth galactic quadrant, between Leo and Boötes, and it is visible in both hemisphere ...

. It lies close to the

North Galactic Pole The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way Galaxy, and the fundamental plane parallel to an ap ...

and has a visual magnitude of approximately 10. It is known as the Needle Galaxy for its narrow profile. First recorded in 1785 by William Herschel, it is a prominent example of an edge-on spiral galaxy.

Characteristics

NGC 4565 is a giant spiral galaxy more luminous than the Andromeda Galaxy.Globular Cluster Systems in Galaxies Beyond the Local Group
/ref> Much speculation exists in literature as to the nature of the central bulge. In the absence of clear-cut dynamical data on the motions of stars in the bulge, the photometric data alone cannot adjudge among various options put forth. However, its exponential shape suggested that it is a barred spiral galaxy. Studies with the help of the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, f ...

not only confirmed the presence of a central bar but also showed a pseudobulge within it as well as an inner ring.Detection of a Distinct Pseudobulge Hidden Inside the ''Box-Shaped Bulge'' of NGC 4565
/ref> NGC 4565 has at least two

satellite galaxies A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents are bound ...

, one of which is

interacting Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to: Science * Interaction hypothesis, a theory of second language acquisition * Interaction (statistics) * Interactions o ...

with it.HALOGAS: H I Observations and Modeling of the Nearby Edge-on Spiral Galaxy NGC 4565
/ref> It has a population of roughly 240 globular clusters, more than the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...

. NGC 4565 is one of the brightest member galaxies of the

Coma I Group The Coma I Group is a group of galaxies located about away in the constellation Coma Berenices. The brightest member of the group is NGC 4725. The Coma I Group is rich in spiral galaxies while containing few elliptical and lenticular galaxies. ...

. This edge-on galaxy exhibits a slightly warped and extended disk under deep optical surveys- likely due to ongoing interactions with neighboring satellite galaxies or other galaxies in the Coma I group. The GALEX image shown below highlights the slight warp at the edge of the disc more clearly than other surveys. Using the

LOw-Frequency ARray The Low-Frequency Array, or LOFAR, is a large radio telescope, with an antenna network located mainly in the Netherlands, and spreading across 7 other European countries as of 2019. Originally designed and built by ASTRON, the Netherlands Institu ...

(LOFAR), astronomers of the

University of Hamburg The University of Hamburg (german: link=no, Universität Hamburg, also referred to as UHH) is a public research university in Hamburg, Germany. It was founded on 28 March 1919 by combining the previous General Lecture System ('' Allgemeines Vor ...

discovered a diffuse

radio halo Radio halos are large-scale sources of diffuse radio emission found in the center of some, but not all, galaxy clusters.Feretti, L., and G. Swarup. "The Universe at Low Radio Frequencies." Proceedings of IAU Symposium. Vol. 199. 2002. There are t ...

around NGC 4565. During the observations, a warp was detected in the radio continuum of NGC 4565 that is reminiscent of a neutral hydrogen line (HI) warp and identifying a slight flaring of the galaxy's radio halo. It is assumed that this flaring is caused by the warp as the vertical intensity profiles are asymmetric, which is in agreement with the warp. According to the study, a minimum age for the warp was estimated at approximately 130 million years. This is the spectral age of the galaxy's

cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...

electrons, during which they are transported into the warp. This indicates that NGC 4565 may be in the aftermath of a period with more intense

star formation Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

References

External links

* *
National Optical Astronomical Observatory
– NGC 4565

– NGC 4565: Galaxy on Edge

– NGC 4565

– NGC 4565 {{DEFAULTSORT:NGC 4565 Unbarred spiral galaxies Coma Berenices 4565 07772 42038 038b Astronomical objects discovered in 1785 Discoveries by William Herschel Coma I Group