Civil Rights
Movements, leaders, victories and the continuing fight for equality.
q2K BHP
Black History Portal
THE BHP WIRE —
HIDDEN TRUTHS
What's New!
Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
Wilmington, North Carolina once had a thriving Black middle class and an elected interracial government. In 1898 white supremacists used violence to overthrow that government, kill Black residents and drive many others from the city.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
 | You can help expand this article with text translated from the corresponding article in Italian. (August 2017) Click [show] for important translation instructions.
|
| RX J1347.5-1145 | |
|---|---|
 Thermal measurement of the Sunyaev-Zeldovich effect in a picture that was taken by the Atacama Large Millimeter Array in Chile showing the blue and violet hues. The Sunyaev-zeldovich effects were taken as the first thermal measurements. | |
| Observation data (Epoch ) | |
| Constellation | Virgo |
| Right ascension | 13h 47m 33.5s[1] |
| Declination | −11° 45′ 42″[1] |
| Redshift | z = 0.451[1] |
| Distance | 5 billion ly (1.533 Gpc) |
| X-ray luminosity | 1×1045 ergs |
RX J1347.5–1145 is one of the most massive galaxy clusters known discovered in X-rays with ROSAT.[2] As a result, it is also one of the most X-ray-luminous because of its hot gas content.[3] The object resides roughly 5 billion light-years away from the Solar System in the constellation of Virgo. Redshift was noted as z=0.451 with an X-ray luminosity of 1045 ergs s−1 in a paper from 2002.[4] In 2013, one study found eight cases of the same object resulting from the intense gravitational bending of light, which makes it possible to identify a series of remote galaxies located inside the galaxy cluster with calculations from the photometric method between 5.5 and 7.5.[5] That study made use of data from Cluster Lensing and Supernova survey with Hubble (CLASH) as well as other sources.[5] The colors in the galaxy cluster are known to correspond with the level of brightness, or the number of electrons trapped in the examined wavelength range of the cluster, with the colors red, orange, and yellow as high intensity, blue-green and green as medium intensity, and blue and violet as low intensity. It is considered one of the brightest objects that is known by X-ray.[6]
The brightest galaxy inside RX J1347.5-1145 is the elliptical GALEX J134730.7-114509. The temperature along with the entropy maps show cool, entropic gases trailing the subcluster in a southwesterly direction, which is consistent with core shredding.[7] The overall gas density, temperature, and metallicity are in good agreement with each other. The hot intracluster medium has an extension to the southeast along with a little indication of two cD galaxies located within the cluster.[8]
The first radio observations were taken in the years of 1999 and 2001 of the Sunyaev-Zeldovich effect located inside RX J1347.5-1145, along with the higher angular resolution (at approximately 150 GHz) which showed the stronger signal along with the enchantment, which is known to be located southeast of the cluster's center, the same location as the surface brightness extension viewed by X-Rays. Since the SZ intensity is proportional to the integrated gas pressure combined along with the light of sight, the strong SZ signal was interpreted due to too much hot gas in the cluster, which was probably caused by the merging of a subcluster along with the primary cluster. The presence of (kT ≥ 15 keV) gas in the southeast portion of the cluster has been cited, reported, and confirmed by Chandra.[9]
The galaxy cluster was observed for over 80 kiloseconds (~22 hours) over three Chandra X-ray Observatory observation windows, which the first two observations were in perspective by ACIS-S and the third one by ACIS-I. The glare projection was known to be done using the 2.5-7 keV and the 9.0-12 keV bands, which excluded the regions that were known to contain point sources and cluster emission.[10]
Proper estimation of the X-Ray background in the galaxy cluster is known to be critical for spectral arrays of faint, extended emission from the cluster, along with the use of the blank sky data sets from the Chandra calibration Database. Overall background normalization was used to measure the ratio of the count rate of high energy frequences (which is known to be around 9-12 keV).[11]
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
RX J1347.5–1145 is one of the most massive galaxy clusters known discovered in X-rays with ROSAT. As a result, it is also one of the most X-ray-luminous because of its hot gas content. The object resides roughly 5 billion light-years away from the Solar System in the constellation of Virgo. Redshift was noted as z=0.451 with an X-ray luminosity of 1045 ergs s−1 in a paper from 2002. In 2013, one study found eight cases of the same object resulting from the intense gravitational bending of light, which makes it possible to identify a series of remote galaxies located inside the galaxy cluster with calculations from the photometric method between 5.5 and 7.5. That study made use of data from Cluster Lensing and Supernova survey with Hubble (CLASH) as well as other sources. The colors in the galaxy cluster are known to correspond with the level of brightness, or the number of electrons trapped in the examined wavelength range of the cluster, with the colors red, orange, and yellow as high intensity, blue-green and green as medium intensity, and blue and violet as low intensity. It is considered one of the brightest objects that is known by X-ray. The brightest galaxy inside RX J1347.5-1145 is the elliptical GALEX J134730.7-114509. The temperature along with the entropy maps show cool, entropic gases trailing the subcluster in a southwesterly direction, which is consistent with core shredding. The overall gas density, temperature, and metallicity are in good agreement with each other. The hot intracluster medium has an extension to the southeast along with a little indication of two cD galaxies located within the cluster.
Lambda Virginis (λ Virginis, abbreviated Lambda Vir, λ Vir) is a binary star system in the zodiac constellation of Virgo. With an apparent visual magnitude of 4.5, it is bright enough to be seen with the naked eye. Based upon parallax measurements, the system is about 173 light-years away from the Sun. Its two components are designated Lambda Virginis A (formally named Khambalia ) and B.
Psi Virginis (ψ Vir, ψ Virginis) is a suspected binary star system in the zodiac constellation of Virgo. It can be seen with the naked eye and has an apparent visual magnitude of about 4.8. Based upon the annual parallax shift of 5.99 milliarcseconds, the distance to this star is roughly 540 light years. The angular size of Psi Virginis was measured on December 26, 1975 during an occultation by the Moon, yielding the estimate 6.5±0.3 mas. The primary component is an evolved red giant star with a stellar classification of M3 IIICa-1. It is an irregular variable with seven measured pulsation periods ranging from 22.4 to 162.6 days, and amplitudes ranging up to 0.m022. The star is a bright X-ray source with a luminosity of 21.58×1029 ergs s−1. There is a magnitude 8.3 companion at an angular separation of 0.04 arcseconds.
Upsilon Virginis (υ Vir, υ Virginis) is a single star in the zodiac constellation of Virgo. It has an apparent visual magnitude of 5.25, making it faintly visible to the naked eye. According to the Bortle scale, it is visible from backlit suburban skies at night. Based upon a measured annual parallax shift of 12.1 mas, it is located roughly 269 light-years (82.6 parsecs) from the Sun. If the star were at a distance of 33 light-years (10 parsecs), it would have a magnitude of +0.4 and be the third-brightest star in the night sky. This star has a stellar classification of G9 III, which indicates it is an evolved G-type giant star. It has an estimated 172% of the Sun's mass and has expanded to 12 times the radius of the Sun, from which it is shining with 64.6 times the solar luminosity. The effective temperature of the star's outer atmosphere is 4,753 K. Based upon its motion through space, there is a 66% chance of being a member of the Hercules stream and a 27% chance it is a thin disk star.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Brown v. Board of Education in 1954.
