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NGC 4535, Virgo, The Lost Galaxy of Copeland, and Five Quasars
NGC 4535, Virgo, The Lost Galaxy of Copeland, and Five Quasars
NGC 4535 is a low surface brightness (LSB) barred spiral galaxy in the constellation Virgo, first documented by William Herschel in 1785. Due to its hazy and "ghostly" visual presentation prominent amateur astronomer Leland Copeland named it "The Lost Galaxy" in the 1950s. Based on its median redshift-independent distance measurement of 51.53 Mly, apparent magnitude of 10.32 (g), and angular size of 7.80 arcmin, the galaxy is approximately 116,000 ly in diameter and 90% as bright as the Milky Way. Its redshift of 0.00657 corresponds to a recession velocity of 1,963 km/s, which is in part due to the expansion of space, and in part to its "peculiar velocity" through space relative to us. Its morphological classification is SAB(s)c, indicating an intermediate-barred spiral galaxy without a central ring, and with moderately wound spiral arms. The galaxy is one of the larger members of the Virgo Galaxy Cluster that includes up to 2,000 members. Like most "cluster spirals" it shows evidence of tidal interaction with other members in the form of spiral arm deformation and splitting, gas depletion, and low average star formation rate (SFR) in the current cosmological epoch. The blue floccules in the spiral structure represent "OB Associations", immense clusters of large and very hot young stars. However, unlike in similar galaxies, these are present in relatively low numbers due to gas depletion in the galactic disk. For this reason, NGC 4535 is regarded as a low surface brightness (LSB) galaxy. A number of curved, elongated structures in the disk strongly resemble "stellar streams", or gravitationally stretched remnants of merged dwarf galaxies. Many major galaxies in the Virgo Cluster show evidence of rapid mass assembly through the process of dwarf galaxy accretion.
NGC 4535 has been extensively investigated regarding the presence of a central supermassive black hole (SMBH). Central black holes have been detected in virtually all substantial galaxies studied. Spectroscopic analysis of the central region in the optical band shows evidence of numerous ionized hydrogen (Hii) clouds. These originate from molecular gas clouds ionized by the powerful ultraviolet radiation emanating either from an SMBH accretion disk and/or circumnuclear regions of new star formation. The width of the spectral lines indicates the "velocity dispersion" of luminous matter near the nucleus, which in turn depends on the intensity of the gravitational field generated by the mass in the galactic center. Studies of NGC 4535 refined the understanding of the relationship between the mass and activity of the central SMBH and the evolution of the galaxy within which it resides. For example, this galaxy's gas depletion and current low average star formation rate are in part due to the return of mass momentum and energy from the black hole to the galaxy by the mechanisms of "SMBH outflows" and "radiation pressure" respectively. These processes expel gas and dust from the galaxy, and are explained in more detail in section 40 here:
www.cloudynights.com/articles/cat/articles/basic-extragal...
While NGC 4535 does not have a central starburst ring structure visible in the optical band, it has been one of the major subjects in recent studies on galactic ring formation (Jiayi Sun et al. 2018). Observational evidence reveals a close association between galactic star formation rate (SFR), molecular gas clouds which are the gas reservoir for star formation, and ionized hydrogen (Hii) regions formed when molecular gas is exposed to ionizing ultraviolet radiation from newborn stars. The hydrogen molecule, H2, originating from the big bang, is by far the main component of molecular gas. The second most abundant component is the carbon monoxide molecule, CO, whose constituent atoms were formed during the preceding generations of "stellar nucleosynthesis". Its emission line at the wavelength of 2.6 mm is used in radio-astronomy to map the distribution of galactic molecular gas clouds. While low mass galaxies show faint and scattered CO emissions, massive spiral galaxies exhibit bright, contiguous ring-like emissions within the galactic bulge (Hughes et al. 2013a). These structures, named "Resonance Rings", are thought to accumulate in regions where the outward acting-forces on the molecules balance the centrally-acting gravitational forces. More precisely, resonance rings form where the kinetic energy of gas molecules, defined by the average "velocity dispersion", balances the gravitational potential energy. The evolution of molecular resonance rings also depends on other mechanisms, such as magnetic fields, central SMBH outflows and radiation pressure, and external gravitational effects and matter exchange related to merging or interacting galaxies. In NGC 4535, a resonance ring was detected approximately 1,500 ly from the center. Under favorable circumstances molecular resonance rings evolve into star-forming regions, and eventually become brightly luminous in the visible band.
Derived properties of identified faint objects are listed in the chart on the annotated image. The most remote are five quasars, four of which lie beyond the "cosmic event horizon", as their recession velocities in the present cosmological epoch are superluminal. Two of them, marked with (+) appear significantly brighter than their listed apparent magnitudes. Many quasars are variable up to several magnitudes with periods ranging from days to years, depending on the inflow of matter available for accretion. The most intrinsically luminous object is LBQS 1232+0815, which is nearly 5,000 times brighter than the Milky Way. The most distant quasar is SDSS J123352.16+080527.4 (z = 2.76700), lying at a light travel distance (lookback time) of 11.33 Bly.
Image details:
-Remote Takahashi TOA 150 x 1105 mm
-OSC 36 x 300 sec, (2021 + 2022), 2x drizzle, 40% linear crop, FOV 31x21 arcmin
-Software: DSS, XnView, Starnet++ v2, StarTools 1.3 and 1.8, Cosmological Calculator 3
NGC 4535, Virgo, The Lost Galaxy of Copeland, and Five Quasars
NGC 4535, Virgo, The Lost Galaxy of Copeland, and Five Quasars
NGC 4535 is a low surface brightness (LSB) barred spiral galaxy in the constellation Virgo, first documented by William Herschel in 1785. Due to its hazy and "ghostly" visual presentation prominent amateur astronomer Leland Copeland named it "The Lost Galaxy" in the 1950s. Based on its median redshift-independent distance measurement of 51.53 Mly, apparent magnitude of 10.32 (g), and angular size of 7.80 arcmin, the galaxy is approximately 116,000 ly in diameter and 90% as bright as the Milky Way. Its redshift of 0.00657 corresponds to a recession velocity of 1,963 km/s, which is in part due to the expansion of space, and in part to its "peculiar velocity" through space relative to us. Its morphological classification is SAB(s)c, indicating an intermediate-barred spiral galaxy without a central ring, and with moderately wound spiral arms. The galaxy is one of the larger members of the Virgo Galaxy Cluster that includes up to 2,000 members. Like most "cluster spirals" it shows evidence of tidal interaction with other members in the form of spiral arm deformation and splitting, gas depletion, and low average star formation rate (SFR) in the current cosmological epoch. The blue floccules in the spiral structure represent "OB Associations", immense clusters of large and very hot young stars. However, unlike in similar galaxies, these are present in relatively low numbers due to gas depletion in the galactic disk. For this reason, NGC 4535 is regarded as a low surface brightness (LSB) galaxy. A number of curved, elongated structures in the disk strongly resemble "stellar streams", or gravitationally stretched remnants of merged dwarf galaxies. Many major galaxies in the Virgo Cluster show evidence of rapid mass assembly through the process of dwarf galaxy accretion.
NGC 4535 has been extensively investigated regarding the presence of a central supermassive black hole (SMBH). Central black holes have been detected in virtually all substantial galaxies studied. Spectroscopic analysis of the central region in the optical band shows evidence of numerous ionized hydrogen (Hii) clouds. These originate from molecular gas clouds ionized by the powerful ultraviolet radiation emanating either from an SMBH accretion disk and/or circumnuclear regions of new star formation. The width of the spectral lines indicates the "velocity dispersion" of luminous matter near the nucleus, which in turn depends on the intensity of the gravitational field generated by the mass in the galactic center. Studies of NGC 4535 refined the understanding of the relationship between the mass and activity of the central SMBH and the evolution of the galaxy within which it resides. For example, this galaxy's gas depletion and current low average star formation rate are in part due to the return of mass momentum and energy from the black hole to the galaxy by the mechanisms of "SMBH outflows" and "radiation pressure" respectively. These processes expel gas and dust from the galaxy, and are explained in more detail in section 40 here:
www.cloudynights.com/articles/cat/articles/basic-extragal...
While NGC 4535 does not have a central starburst ring structure visible in the optical band, it has been one of the major subjects in recent studies on galactic ring formation (Jiayi Sun et al. 2018). Observational evidence reveals a close association between galactic star formation rate (SFR), molecular gas clouds which are the gas reservoir for star formation, and ionized hydrogen (Hii) regions formed when molecular gas is exposed to ionizing ultraviolet radiation from newborn stars. The hydrogen molecule, H2, originating from the big bang, is by far the main component of molecular gas. The second most abundant component is the carbon monoxide molecule, CO, whose constituent atoms were formed during the preceding generations of "stellar nucleosynthesis". Its emission line at the wavelength of 2.6 mm is used in radio-astronomy to map the distribution of galactic molecular gas clouds. While low mass galaxies show faint and scattered CO emissions, massive spiral galaxies exhibit bright, contiguous ring-like emissions within the galactic bulge (Hughes et al. 2013a). These structures, named "Resonance Rings", are thought to accumulate in regions where the outward acting-forces on the molecules balance the centrally-acting gravitational forces. More precisely, resonance rings form where the kinetic energy of gas molecules, defined by the average "velocity dispersion", balances the gravitational potential energy. The evolution of molecular resonance rings also depends on other mechanisms, such as magnetic fields, central SMBH outflows and radiation pressure, and external gravitational effects and matter exchange related to merging or interacting galaxies. In NGC 4535, a resonance ring was detected approximately 1,500 ly from the center. Under favorable circumstances molecular resonance rings evolve into star-forming regions, and eventually become brightly luminous in the visible band.
Derived properties of identified faint objects are listed in the chart on the annotated image. The most remote are five quasars, four of which lie beyond the "cosmic event horizon", as their recession velocities in the present cosmological epoch are superluminal. Two of them, marked with (+) appear significantly brighter than their listed apparent magnitudes. Many quasars are variable up to several magnitudes with periods ranging from days to years, depending on the inflow of matter available for accretion. The most intrinsically luminous object is LBQS 1232+0815, which is nearly 5,000 times brighter than the Milky Way. The most distant quasar is SDSS J123352.16+080527.4 (z = 2.76700), lying at a light travel distance (lookback time) of 11.33 Bly.
Image details:
-Remote Takahashi TOA 150 x 1105 mm
-OSC 36 x 300 sec, (2021 + 2022), 2x drizzle, 40% linear crop, FOV 31x21 arcmin
-Software: DSS, XnView, Starnet++ v2, StarTools 1.3 and 1.8, Cosmological Calculator 3