View allAll Photos Tagged hierarchical
Sunday, July 3, 2016 â NASHVILLE, Tenn. â Almost a thousand people attended the Hierarchical Divine Liturgy this morning that began the 43rd Biennial Clergy-Laity Congress of the Greek Orthodox Archdiocese of America.
The Orthros service and Hierarchical Concelebration of the Divine Liturgy were held in the Grand Ole Opry House.
His Eminence Archbishop Demetrios Geron of America presided over the Divine Liturgy concelebrating with all the Metropolitans of the Holy Eparchial Synod of the Archdiocese. Taking part in the Liturgy were His Eminence Metropolitan Iakovos of Chicago, His Eminence Metropolitan Methodios of Boston, His Eminence Metropolitan Isaiah of Denver, His Eminence Metropolitan Alexios of Atlanta, His Eminence Metropolitan Nicholas of Detroit (the host Metropolitan of this yearâ s Congress), His Eminence Metropolitan Savas of Pittsburgh, His Eminence Metropolitan Gerasimos of San Francisco, and His Eminence Metropolitan Evangelos of New Jersey.
Îε Ïην ÏÎ-λεÏη ΣÏ
Î½Î¿Î´Î¹ÎºÎ®Ï ÎÎµÎ¯Î±Ï ÎειÏοÏ
ÏÎ³Î¯Î±Ï ÏÏο Grand Ole Opry House ÏÏοεξάÏÏονÏÎ¿Ï ÏοÏ
ÎÏÏιεÏιÏκÏÏοÏ
ÎÎ-ÏονÏÎ¿Ï ÎμεÏÎ¹ÎºÎ®Ï Îº. ÎημηÏÏίοÏ
ξεκίνηÏαν ÏήμεÏα ÏÏο ÎάÏβιλ ÏοÏ
ΤενεÏί οι εÏγαÏÎ¯ÎµÏ ÏÎ·Ï 43Î·Ï ÎληÏικολαÏÎºÎ®Ï Î£Ï
νÎ-λεÏ
ÏÎ·Ï ÏÎ·Ï ÎεÏÎ¬Ï ÎÏÏιεÏιÏκοÏÎ®Ï ÎμεÏικήÏ.
ΣÏ
λλειÏοÏÏγηÏαν ο ÎηÏÏοÏολίÏÎ·Ï Î£Î¹ÎºÎ¬Î³Î¿ κ. ÎάκÏβοÏ, ο ÎηÏÏοÏολίÏÎ·Ï ÎοÏÏÏÎ½Î·Ï Îº.ÎεθÏδιοÏ, ο ÎηÏÏοÏολίÏÎ·Ï ÎÏÎ-Î½Î²ÎµÏ Îº.ÎÏαÏαÏ, ο ÎηÏÏοÏολίÏÎ·Ï ÎÏλάνÏÎ±Ï Îº.ÎλÎ-ξιοÏ, ο ÎηÏÏοÏολίÏÎ·Ï ÎÏηÏÏÏÎ¹Ï Îº.ÎικÏλαοÏ, ο ÎηÏÏοÏολίÏÎ·Ï Î Î¹ÏÏβοÏÏγοÏ
κ.ΣάββαÏ, ο ÎηÏÏοÏολίÏÎ·Ï ÎγίοÏ
ΦÏαγκίÏκοÏ
κ.ÎεÏάÏÎ¹Î¼Î¿Ï ÎºÎ±Î¹ ο ÎηÏÏοÏολίÏÎ·Ï ÎÎ-Î±Ï ÎεÏÏÎ-Î·Ï Îº.ÎÏ
άγγελ
Bishnu Maya (second from right) watches with her neighbors a video interview of herself speaking about her life as a maize farmer. Maya, from Belhara village, Dhankuta district, in the mid-hills of Nepal, is a widowed mother of three and a "dalit," meaning she is a member of one of the poorest castes, considered "untouchable" in Nepal’s traditional hierarchical system. She works hard, devoting the majority of her 0.6 hectares to maize, but also tending millet, tomatoes, cucumbers, and various livestock. However, traditional maize varieties have only one small ear per plant and are prone to lodging (i.e., falling over), and Maya was never able to grow enough for the whole year. She struggled to feed her family and to send her children to school.
Maya's life began to change when she was invited to take part in participatory evaluations of improved maize varieties developed for the mid-hills region. The project was part of the Hill Maize Research Program (HMRP), a long-term collaboration between CIMMYT, the Nepal Agricultural Research Council (NARC), and other partners. Ram Bahadur Katuwal (right), then agronomist at NARC's Pakhribas Agriculture Research Station and currently cluster agronomist of the HMRP, worked directly with Maya and other farmers to help them choose new varieties to try, as well new crop management practices. Maya decided to plant a variety called Manakamana-3, which with its two large ears per plant gave her higher yields, as well as resisting lodging and staying green as it matured, making a better feed for her livestock. The project also advised Maya to plant intercropped vegetables in addition to maize, bringing her additional food and income. “Now I have enough food and can sell some surplus to pay for my children’s education," she says. "Now they are studying and I am hopeful that their livelihoods would be improved."
The project focused on women farmers and disadvantaged groups like dalits, testing and promoting technologies that could be implemented by the farmers themselves. Participating farmers have observed 20-50% higher grain yields with the new varieties. "We know this program is for us. We would not have participated in the trials if it wasn't," says Maya. She now demonstrates the new variety to other farmers.
According to a report released in 2010, more than two decades of joint efforts between researchers from Nepal and CIMMYT have helped boost the country's maize yields 36% and those of wheat by 85%. As a result, farmers even in the country's remote, mid-hill mountain areas have more food and brighter futures.
Photo credit: D. Mowbray/CIMMYT.
For more on the HMRP and CIMMYT's relationship with Nepal, see the following:
2010 e-news, "Nepal-CIMMYT partnerships reach the unreached": www.cimmyt.org/en/about-us/media-resources/newsletter/869....
2006 e-news, "People of the Clouds": www.cimmyt.org/en/about-us/media-resources/newsletter/254....
Nepal-related stories on CIMMYT's blog: blog.cimmyt.org/?s=nepal.
The final CIMMYT video "Maize for Life", featuring Bishnu Maya as one of three women discussing their lives as maize farmers, is available at: www.youtube.com/watch?v=5ls53idLkUg.
All brown bears live by an unspoken hierarchy, but one that is very much known amongst their kind nonetheless. The Katmai NP brown bears are no different.
These bears generally prefer to live in their own territorial space, but when the food is plentiful, such as when the salmon are running, or when they have other things on their mind, like attracting a female to mate with, they find a way to co-exist. That doesn't mean that confrontations don't happen.
In this image, these two males were challenging each other for the affection of one of the nearby females. In the enormity of the wilderness and grassy areas to feed upon, they managed to cross paths. I, being totally against blood shed of these amazing creatures, was preparing myself for the worse.... having never been witnessed to the bears in the mating season. I wondered.... would they defend their own right fiercely by fighting upright, with their ferocious growling and snapping? Would it be quick or long and drawn out? Would a winner ever be declared?
to my surprise, these two met face-to-face or should I say muzzle-to-muzzle and gave long deep growls of warning. Hackles became prominent and the saliva was flowing and the stand-off was on. It did, however, end peacefully as the smaller of the two, who by the way started the whole confrontation, realized he might as well quit while he was ahead - so he just dropped his head and began grazing on the green grass. The "winner" then did the same.... as if nothing had ever happened!
It's quite fascinating to watch the behavior of these powerful animals. It's also amazing to see how they yield to the hierarchy that exists in their world and, in doing so, co-exist for the time.
Thanks for stopping by to view and comment, as they are both greatly appreciated. I'll have another week or so of Alaska images, then start mixing them in again.
Happy Hump Day!
en.wikipedia.org/wiki/Maslow's_hierarchy_of_needs
FYI: I prefer ERG theory (Existence, Relatedness and Growth).
en.wikipedia.org/wiki/ERG_theory
www.valuebasedmanagement.net/methods_alderfer_erg_theory....
Pics from various XML code just made up out of copied parts. Made it up to 400 nodes. Some were pre-auto adjusting node size.
"But who polices that police police?"
This is a linguistics joke:
en.wikipedia.org/wiki/Buffalo_buffalo_Buffalo_buffalo_buf...
From my animation "Police Show Commercial": www.youtube.com/watch?v=YdyY1qR6gps
Almost all biomedical ontologies are either simple tree structures that represent hierarchical classifications or directed acyclic graphs (DAGs). The difference is that the latter allows a term to be related to multiple broader tems (green arrows) whereas the former does not. Directed cyclic graphs are very rarely used for ontologies; the reason is that cycles (red arrows) can only arise in ontologies that make use of other relationships than is-a and part-of are used [28]. We illustrate each structure with simplified examples, namely an ontology of vertebrates, an ontology of cellular components, and an ontology of cell-cycle regulation that shows the mutual regulation of cyclin-dependent kinase (CDK) and anaphase-promoting complex/cyclosome (APC/C).
doi:10.1371/journal.pbio.1000374.g001
Taken from Figure 1 of Ontologies in Quantitative Biology by Lars Juhl Jensen and Peer Bork
(page 3 of 5)
We are, therefore, sending this appeal to each member of the Irish Hierarchy, who will, we trust, take it as coming not so much from us as from the Catholic Soldiers in France, and in the East, who cannot themselves voice their claims and wishes.
Signatures
His Hon. Judge Brereton Barry, K.C., Langara, Glengeary, Co Dublin.
Philip Harold-Barry, J.P., Ballyyellis, Buttevant, Co. Cork
Sir Henry Bellington, Bart., H.M.J., Bellingham Castle, Co. Louth.
William Bergin, M.A., Professor of Physics, University College, Cork.
Thomas Boylan, J.P., Hilltown, Drogheda.
Edward T Boylan, Lieut., R.H.A.
Francis M Boylan.
Stephen J. Brown, Ard Caein, Co. Kildare.
Thomas Butler, 97 Baggot Street, Dublin
George Byrne, 30 Elgin Road, Dublin.
Sir Arthur Chance, F.R.C.S.I., 90 Merrion Square, Dublin.
Elias B. Corbally, Rathbeal Hall, Swords, Co. Dublin.
Right Hon. Micheal F. Fox, P.C., M.D., LL.D., F.R.C.P.I., 26 Merrion Square, Dublin.
Col. Gerald Dease, D.L., J.P., Turbotstown, Co. Westmeath.
Edmund F. Dease, J.P., Culmullen, Drumree, Co Meath.
Sir Henry Doran, Clonard, Terenure, Co. Dublin.
John T. Dudley, 60 Wellington Road, Dublin.
P. J. Davy, Killaghbeg, Galway.
J. O’Dowd Egan.
Capt. John Edward Farrell, D.L., Moynalty House, Co. Meath.
William Gallwey, J.P., Rockfield, Tramore, Co. Waterford.
His Hon. Judge George C. Green, K.C., Herberton, Blackrock, Co. Dublin.
Stephen Greham, D.L., Clonmeen, Banteer, Co. Cork.
Brig.-General Dayrell T. Hammond, C.B., Curragh Camp.
Sir Henry Harrington, Kt., Commissioner of National Education, Co. Cork.
Raoul Joyce, Glenina, Galway.
Earl Of Kenmare, Killarney House, Co. Kerry.
Surgeon Lieut.-Col. C. R. Kilkelly, Grenadier Guards, Drimcong, Moycullen, Co.
Galway
F. St. John Lacy, F.R.A.M., Professor of Music, University College, Cork.
T. J. Leary, High Sheriff, Woodford, Mallow, Co. Cork.
C. E. T. Leslie, J.P., Killowen, Co. Down.
Sir John P. Lynch, Belfield, Stillorgan Road, Dublin.
James Mahony, 7 Raglan Road, Dublin.
George Mansfield, H.M., Vice-Lieutenant, Morristown-Lattin, Naas, Co. Kildare.
C. O. Martin, 28 Clyde Road, Dublin.
J. M. Maxwell, J.P., Roxboro’ Road, Dublin.
P. J. Merriman, M.A., Professor of History and Registrar, University College, Cork.
M. J. Minch, Clonfadda, Blackrock, Dublin.
Joseph Mooney, Cabra Lodge, Dublin.
Sir Walter Nugent, Bart., M.P., Donore, Co. Westmeath.
J. R. O’Brien, 6 Lesson Park, Dublin.
Sir Morgan O’Connell, Bart., D.L., Lakeview, Killarney.
Sir John R. O’Connell, M.A., Ll.D., 34 Kildare Street, Dublin.
John O’Conor, Solicitor, Congested Districts Board, 4 New Brighton, Monkstown.
O’Conor Don, H.M.L., Clonalis, Castlerea, Co. Roscommon.
Charles H. O’Conor, Taney House, Dundrum, Dublin.
Thomas A. O’Farrell, 30 Landsdowne Road, Dublin.
Richard O’Hagen, Killowen, Co.Down.
Major John Ed. Loftus, Machine Gun Corps., Mount Loftus, Co. Kilkenny.
Sir Albert Meldon, Knt, J.P., Vevay House, Bray.
Rt. Hon. Lord Justice Molony, 35 Fitswilliam Place, Dublin.
The MacDermot, D.L., Coolavin, Co. Sligo.
Major John Murray, XIV Hussars.
John O’Neill, J.P., The Pointneb, Killowen, Co. Down.
P. J. O’Neill, J.P., Chairman, Co Dublin Co. Council, Kinsealy House, Malahide.
Joseph O’Reilly, D.L., Sans Souci, Booterstown, Co. Dublin.
P. J. O’Sullivan, M.D. Professor of Medical Jurisprudence, University College, Cork.
Rt. Hon. Christopher Palles, P.C., Mount Anville House, Dundrum, Co. Dublin.
Thomas L. Plunkett, D.L., Portmarnock House, Co. Dublin.
(Mrs) A. Purcell, Buttevant , Co. Cork.
Sir John Ross Of Bladensburg, K.C.B., D.L., Rostrever House, Co Down.
William Ryan, Anerly, Cowper Road, Dublin.
George Ryan, D.L., Inch, Thurles, Co. Tipperary.
Mary Ryan, M.A., Professor, Romance Languages, University College, Cork.
Fras. S. Sheridan, 7 Pembroke Road, Dublin.
J. Smiddy, M.A., Professor of Economics and Warden of Honan Hostel, University
College, Cork.
Alfred Smith, F.R.C.S.I., 30 Merrion Square, Dublin.
Joseph Smyth, J.P., M.D., Green Awn, Gowra, Naas.
Sir Thomas Stafford, Bart, D.L., Rockinghan, Co. Roscommon.
J. Gaiaford St. Lawrence, D.L., Howth Castle, Co. Dublin.
James M. Sweetman, K.C., J.P., Longtown, Sallins, Co. Kildare.
Mary P. Synnott, Innismmore, Glenigeary, Co. Dublin.
Nicholas J. Synnott, J.P., Furness, Naas, Co. Kildare.
Thomas Tyrrell, Castleknock, Co. Dublin.
J. Chester Walsh, R.F.C.
Sir Bertram C. A. Windle, Kt., K.S.G, President, University College, Cork,
Vice-Chancellor, N.U.I.
W. J. Walsh, J.P., Kingswood, Clondalkin, Co. Dublin.
Sir Thomas Talbot Power, Bart., Thornhill, Stillorgan.
Lewis Farrell, 34 Lower Baggot Street, Dublin, Director, John Power & Sons, Ltd.
Martin Fitzgerald, J.P. Ardilree, Dundrum, Co Dublin.
C. Fortrell, 4 Raglan Road, Dublin.
Edward J. Andrews, 18 Belgrave Square, Rathmines.
Bernard Jas. Mcdonnell, Monte Rosa. Dalkey.
George Power Lalor, J.P., Long Orchard, Templemore.
W.G. De La Poer, J.P., Long Orchard, Templemore.
John Delany Cook, J.P., Brownstown, Templemore.
Major J. S. Cape, R.F.A., Ballymanny, Newbridge.
R. J. Kelly, K.C., 45 Wellington Road, Dublin.
Frederica S. Chevers, Killyan, Balinasloe.
John J. Chevers, D.L., Killyan, Balinasloe.
Walter J. O’Kelly, J.P., Knockavannie, Tuam,
(Mrs) L. A. D’arcy, New Forrest, Ballinamore Bridge, Co. Galway.
(Mrs) J. Julia C. A. Daly, Oriel Temple, Co. Louth.
James M. Magee, J.P., Chairman, Bray U.D.C.
D. J. Roantree, M.B. B.Ch., Bray U.D.C.
Hugh Thos. O’Carroll, Bray U.D.C.
Joseph M. Reigh, J.P., M.C.C., P.L.G., Bray U.D.C.
Martin Langton, J.P., M.C.C., P.L.G., Bray U.D.C.
J. G. Marnan, Barrister-at-Law.
John J. L. Murphy, Solicitor.
H. J. Raverty, M.B., D.P.H.
John Bergin, P.L.G., M.D.C.
Denis Mullally, Town Clerk, Bray.
Malachy Mackey, U.D.C.
James Carberry, P.L.G.
Sir James Murphy, Bart., D.L., Yapton, Monkstown, Co. Dublin.
W. Fitzgerald, 13 Raglan Road, Dublin.
J. St. John Coleman, 42 Belgrave Square, Rathmnes.
Jos. X. Murphy, 10 Clyde Road, Dublin.
N. Comyn, J.P., Ballinderry, Co. Galway.
J. M. Comyn, Ballinderry, Co. Galway.
N. O’C. Comyn, J.P., Ballinderry, Co. Galway.
Lt.-Col. L. G. Esmore, Commanding, 11th R. Dublin Fusiliers.
Capt. John I. Esmonde, 10th R. D. Fusiliers, M.P., British Expeditionary Force.
Major P. H. O’Hara, 11th R. Dublin Fusiliers.
Rt. Hon. W. Kenny, Judge of The High Court Of Justice, Marlfield, Cabinteely,
Co. Dublin.
David Sherlock, D.L., J.P. Barrister-at-Law, Rahan, Kings County.
Pics from various XML code just made up out of copied parts. Made it up to 400 nodes. Some were pre-auto adjusting node size.
To facilitate broad-based innovation in teaching and learning, library & IT organizations must first address a hierarchy of faculty needs.
This concept was shared in the February 15, 2012 presentation, "Setting the Stage for Success: A Discussion of Insights from the MISO Survey" at the ELI 2012 Annual Meeting. It has also been presented in an EDU-ISIS seminar session, presented on July 20, 2012.
Concept: Kevin J.T. Creamer
Design: Hil Scott
The Entrepreneur SuperStar Success Hierarcy by Jennie Armato
Why-To and How-To Implement Your Own Hierarchy of Entrepreneur Success is the foundation of the teachings at Jen's upcoming Live Event "The Entrepreneur SuperStar Intensive".
At this event, you will learn HOW to construct and implement your own Sustainable Income Success Hierarcy, following a Proven Blueprint.
25-27 February 2011, Melbourne Australia.
Registration opens soon, mark the dates in your diary NOW! Attendees numbers ARE Limited.
Bonus Closed-door Mastermind on 28 Feb, only for affiliates (you have to reward loyalty, it's your greatest honor).
IF YOU DIG IT, SHARE IT, I'LL LOVE YOU FOR IT!
Above the shields of the nobility are bishops and abbots, saints, apostles and angels.
The Great East Window, Gloucester Cathedral.
Here is an infographic that depicts information about hierarchical structure of two top internet giants, Facebook and Google. It briefs about the roles of various professionals divided in to various departments. It also states the list of directors working under a CEO with strong leader ship qualities working with a aim to dominate the internet world.
Image of one of Wolfgang Bauer's pieces from the upcoming exhibition 'Spring Awakenings', May 2007, at Found Gallery. See www.foundla.com for more information.
Highlighted "Opera" as the key term for this poster since the word itself can attract opera enthusiasts quicker. Paraphrased some of the sentences to make it more fluid and less formal.
Pics from various XML code just made up out of copied parts. Made it up to 400 nodes. Some were pre-auto adjusting node size.
Climate science is often confusing. However, there are a number of relatively simple ways to frame the issue.
This diagram includes the main elements of climate science, moving from emissions to impacts. It also includes, in the coloured boxes, elements that are often overlooked or forgotten by non-scientists.
Captured 15 Jun 2021, 22:49 hrs ET, Springfield, VA, USA. Bortle 8 skies, Mallincam DS10C camera, Celestron 8 inch SCT f/10, exposure 20 sec, gain 20, bin 2, stack of 100 light frames, dark and flat frames subtracted, no filter.
Clouds: partly cloudy
Seeing: ok
Transparency: ok
Moon phase: 37%
FOV: 29 x 22 arcmin before crop
Resolution: 0.9 arcsec/pixel
Orientation: Up is South
Appearance: group of dim galaxies. NGC6166 is the nebulous object (small nebulosity with two light 'eyes') just right of center and NGC6158 is at 7:30 o'clock.
From NED: NGC 6166
Apparent magnitude: +11.8
Apparent size: 2 arcmin
Distance: 429 million light years
Redshift: z = 0.030
Type: cD
Age: 97% of the age of the Universe
From the Wikipedia:
Abell 2199 is a galaxy cluster in the Abell catalogue featuring a brightest cluster galaxy NGC 6166, a cD galaxy. Abell 2199 is the definition of a Bautz-Morgan type I cluster due to NGC 6166.
A brightest cluster galaxy (BCG) is defined as the brightest galaxy in a cluster of galaxies. BCGs include the most massive galaxies in the universe. They are generally elliptical galaxies which lie close to the geometric and kinematical center of their host galaxy cluster, hence at the bottom of the cluster potential well. They are also generally coincident with the peak of the cluster X-ray emission.
Formation scenarios for BCGs include:
Cooling flow—Star formation from the central cooling flow in high density cooling centers of X-ray cluster halos.
The study of accretion populations in BCGs has cast doubt over this theory and astronomers have seen no evidence of cooling flows in radiative cooling clusters. The two remaining theories exhibit healthier prospects.
Galactic cannibalism—Galaxies sink to the center of the cluster due to dynamical friction and tidal stripping.
Galactic merger—Rapid galactic mergers between several galaxies take place during cluster collapse.
It is possible to differentiate the cannibalism model from the merging model by considering the formation period of the BCGs. In the cannibalism model, there are numerous small galaxies present in the evolved cluster, whereas in the merging model, a hierarchical cosmological model is expected due to the collapse of clusters. It has been shown that the orbit decay of cluster galaxies is not effective enough to account for the growth of BCGs. The merging model is now generally accepted as the most likely one, but recent observations are at odds with some of its predictions. For example, it has been found that the stellar mass of BCGs was assembled much earlier than the merging model predicts.
BCGs are divided into various classes of galaxies: giant ellipticals (gE), D galaxies and cD galaxies. cD and D galaxies both exhibit an extended diffuse envelope surrounding an elliptical-like nucleus akin to regular elliptical galaxies. The light profiles of BCGs are often described by a Sersic surface brightness law, a double Sersic profile or a de Vaucouleurs law. The different parametrizations of the light profile of BCG's, as well as the faintness of the diffuse envelope lead to discrepancies in the reported values of the sizes of these objects.
The Bautz–Morgan classification was developed in 1970 by Laura P. Bautz and William Wilson Morgan to categorize galaxy clusters based on their morphology. It defines three main types: I, II, and III. Intermediate types (I-II, II-III) are also allowed. A type IV was initially proposed, but later redacted before the final paper was published.
A type I cluster is dominated by a bright, large, supermassive cD galaxy; for example Abell 2029 and Abell 2199. A type II cluster contains elliptical galaxies whose brightness relative to the cluster is intermediate to that of type I and type III. The Coma Cluster is an example of a type II. A type III cluster has no remarkable members, such as the Virgo Cluster. Type III has two subdivisions, type IIIE and type IIIS. Type IIIE clusters do not contain many giant spirals. Type IIIS clusters contain many giant spirals. The deprecated type IV was for clusters whose brightest members were predominantly spirals.
NGC 6166 is an elliptical galaxy in the Abell 2199 cluster. It lies 490 million light years away in the constellation Hercules. The primary galaxy in the cluster, it is one of the most luminous galaxies known in terms of X-ray emissions. NGC 6166 is a radio-loud quasar.
NGC 6166 is a supermassive, type cD galaxy, with several smaller galaxies within its envelope.
Suspected to have formed through a number of galaxy collisions, NGC 6166 has a large number of globular clusters (estimated as between 6,200 and 22,000 in 1996) orbiting the galaxy. A 2016 study, however, gave an even higher number (around 39,000) suggesting also that the halo of this galaxy blends smoothly with the intra-cluster medium. Because of that, the galaxy has richest globular cluster system known. The galaxy harbors a supermassive black hole at its center with a mass of nearly 30 billion M☉ based on dynamical modelling.
NGC 6166 is known to host an active nucleus, classified as an FR I source, which powers two symmetric parsec-scale radio jets and radio lobes and it is caused by the infall of gas into its center caused by a cooling flow that deposits 200 solar masses of gas every year there.
It has been proposed that a number of O-type stars may be present in the center of NGC 6166.
The Abell catalog of rich clusters of galaxies is an all-sky catalog of 4,073 rich galaxy clusters of nominal redshift z ≤ 0.2. This catalog supplements a revision of George O. Abell's original "Northern Survey" of 1958, which had only 2,712 clusters, with a further 1,361 clusters – the "Southern Survey" of 1989, published after Abell's death by co-authors Harold G. Corwin and Ronald P. Olowin from those parts of the south celestial hemisphere that had been omitted from the earlier survey.
The Abell catalog, and especially its clusters, are of interest to amateur astronomers as challenge objects to be viewed in dark locations on large aperture amateur telescopes.
A quasar (/ˈkweɪzɑːr/; also known as a quasi-stellar object, abbreviated QSO) is an extremely luminous active galactic nucleus (AGN), in which a supermassive black hole with mass ranging from millions to billions of times the mass of the Sun is surrounded by a gaseous accretion disk. As gas in the disk falls towards the black hole, energy is released in the form of electromagnetic radiation, which can be observed across the electromagnetic spectrum. The power radiated by quasars is enormous; the most powerful quasars have luminosities thousands of times greater than a galaxy such as the Milky Way. Usually, quasars are categorized as a subclass of the more general category of AGN. The redshifts of quasars are of cosmological origin.
The term quasar originated as a contraction of quasi-stellar [star-like] radio source – because quasars were first identified during the 1950s as sources of radio-wave emission of unknown physical origin – and when identified in photographic images at visible wavelengths, they resembled faint, star-like points of light. High-resolution images of quasars, particularly from the Hubble Space Telescope, have demonstrated that quasars occur in the centers of galaxies, and that some host galaxies are strongly interacting or merging galaxies. As with other categories of AGN, the observed properties of a quasar depend on many factors, including the mass of the black hole, the rate of gas accretion, the orientation of the accretion disk relative to the observer, the presence or absence of a jet, and the degree of obscuration by gas and dust within the host galaxy.
Quasars are found over a very broad range of distances, and quasar discovery surveys have demonstrated that quasar activity was more common in the distant past. The peak epoch of quasar activity was approximately 10 billion years ago.
More than a million quasars have been found. The nearest known quasar is about 600 million light-years away (Markarian 231).
The record for the most distant known quasar keeps changing. In 2017, the quasar ULAS J1342+0928 was detected at redshift z = 7.54. Light observed from this 800 million solar mass quasar was emitted when the universe was only 690 million years old. In 2020, the quasar Pōniuāʻena was detected from a time only 700 million years after the Big Bang, and with an estimated mass of 1.5 billion times the mass of our Sun. In early 2021, the quasar J0313-1806, with a 1.6 billion solar-mass black hole, was reported at z = 7.64, 670 million years after the Big Bang. In March 2021, PSO J172.3556+18.7734 was detected and has since been called the most distant known radio-loud quasar discovered.
The term "quasar" was first used in an article by astrophysicist Hong-Yee Chiu in May 1964, in Physics Today, to describe certain astronomically-puzzling objects:
So far, the clumsily long name "quasi-stellar radio sources" is used to describe these objects. Because the nature of these objects is entirely unknown, it is hard to prepare a short, appropriate nomenclature for them so that their essential properties are obvious from their name. For convenience, the abbreviated form "quasar" will be used throughout this paper.
Between 1917 and 1922, it became clear from work by Heber Curtis, Ernst Öpik and others, that some objects ("nebulae") seen by astronomers were in fact distant galaxies like our own. But when radio astronomy commenced in the 1950s, astronomers detected, among the galaxies, a small number of anomalous objects with properties that defied explanation.
The objects emitted large amounts of radiation of many frequencies, but no source could be located optically, or in some cases only a faint and point-like object somewhat like a distant star. The spectral lines of these objects, which identify the chemical elements of which the object is composed, were also extremely strange and defied explanation. Some of them changed their luminosity very rapidly in the optical range and even more rapidly in the X-ray range, suggesting an upper limit on their size, perhaps no larger than our own Solar System. This implies an extremely high power density. Considerable discussion took place over what these objects might be. They were described as "quasi-stellar [meaning: star-like] radio sources", or "quasi-stellar objects" (QSOs), a name which reflected their unknown nature, and this became shortened to "quasar".
The first quasars (3C 48 and 3C 273) were discovered in the late 1950s, as radio sources in all-sky radio surveys. They were first noted as radio sources with no corresponding visible object. Using small telescopes and the Lovell Telescope as an interferometer, they were shown to have a very small angular size. By 1960, hundreds of these objects had been recorded and published in the Third Cambridge Catalogue while astronomers scanned the skies for their optical counterparts. In 1963, a definite identification of the radio source 3C 48 with an optical object was published by Allan Sandage and Thomas A. Matthews. Astronomers had detected what appeared to be a faint blue star at the location of the radio source and obtained its spectrum, which contained many unknown broad emission lines. The anomalous spectrum defied interpretation.
British-Australian astronomer John Bolton made many early observations of quasars, including a breakthrough in 1962. Another radio source, 3C 273, was predicted to undergo five occultations by the Moon. Measurements taken by Cyril Hazard and John Bolton during one of the occultations using the Parkes Radio Telescope allowed Maarten Schmidt to find a visible counterpart to the radio source and obtain an optical spectrum using the 200-inch (5.1 m) Hale Telescope on Mount Palomar. This spectrum revealed the same strange emission lines. Schmidt was able to demonstrate that these were likely to be the ordinary spectral lines of hydrogen redshifted by 15.8%, at the time, a high redshift (with only a handful of much fainter galaxies known with higher redshift). If this was due to the physical motion of the "star", then 3C 273 was receding at an enormous velocity, around 47000 km/s, far beyond the speed of any known star and defying any obvious explanation. Nor would an extreme velocity help to explain 3C 273's huge radio emissions. If the redshift was cosmological (now known to be correct), the large distance implied that 3C 273 was far more luminous than any galaxy, but much more compact. Also, 3C 273 was bright enough to detect on archival photographs dating back to the 1900s; it was found to be variable on yearly timescales, implying that a substantial fraction of the light was emitted from a region less than 1 light-year in size, tiny compared to a galaxy.
Although it raised many questions, Schmidt's discovery quickly revolutionized quasar observation. The strange spectrum of 3C 48 was quickly identified by Schmidt, Greenstein and Oke as hydrogen and magnesium redshifted by 37%. Shortly afterwards, two more quasar spectra in 1964 and five more in 1965 were also confirmed as ordinary light that had been redshifted to an extreme degree. While the observations and redshifts themselves were not doubted, their correct interpretation was heavily debated, and Bolton's suggestion that the radiation detected from quasars were ordinary spectral lines from distant highly redshifted sources with extreme velocity was not widely accepted at the time.
An extreme redshift could imply great distance and velocity but could also be due to extreme mass or perhaps some other unknown laws of nature. Extreme velocity and distance would also imply immense power output, which lacked explanation. The small sizes were confirmed by interferometry and by observing the speed with which the quasar as a whole varied in output, and by their inability to be seen in even the most powerful visible-light telescopes as anything more than faint starlike points of light. But if they were small and far away in space, their power output would have to be immense and difficult to explain. Equally, if they were very small and much closer to our galaxy, it would be easy to explain their apparent power output, but less easy to explain their redshifts and lack of detectable movement against the background of the universe.
Schmidt noted that redshift is also associated with the expansion of the universe, as codified in Hubble's law. If the measured redshift was due to expansion, then this would support an interpretation of very distant objects with extraordinarily high luminosity and power output, far beyond any object seen to date. This extreme luminosity would also explain the large radio signal. Schmidt concluded that 3C 273 could either be an individual star around 10 km wide within (or near to) our galaxy, or a distant active galactic nucleus. He stated that a distant and extremely powerful object seemed more likely to be correct.
Schmidt's explanation for the high redshift was not widely accepted at the time. A major concern was the enormous amount of energy these objects would have to be radiating, if they were distant. In the 1960s no commonly accepted mechanism could account for this. The currently accepted explanation, that it is due to matter in an accretion disc falling into a supermassive black hole, was only suggested in 1964 by Edwin Salpeter and Yakov Zel'dovich, and even then it was rejected by many astronomers, because in the 1960s, the existence of black holes was still widely seen as theoretical and too exotic, and because it was not yet confirmed that many galaxies (including our own) have supermassive black holes at their center. The strange spectral lines in their radiation, and the speed of change seen in some quasars, also suggested to many astronomers and cosmologists that the objects were comparatively small and therefore perhaps bright, massive and not far away; accordingly that their redshifts were not due to distance or velocity, and must be due to some other reason or an unknown process, meaning that the quasars were not really powerful objects nor at extreme distances, as their redshifted light implied. A common alternative explanation was that the redshifts were caused by extreme mass (gravitational redshifting explained by general relativity) and not by extreme velocity (explained by special relativity).
Various explanations were proposed during the 1960s and 1970s, each with their own problems. It was suggested that quasars were nearby objects, and that their redshift was not due to the expansion of space (special relativity) but rather to light escaping a deep gravitational well (general relativity). This would require a massive object, which would also explain the high luminosities. However, a star of sufficient mass to produce the measured redshift would be unstable and in excess of the Hayashi limit. Quasars also show forbidden spectral emission lines, previously only seen in hot gaseous nebulae of low density, which would be too diffuse to both generate the observed power and fit within a deep gravitational well. There were also serious concerns regarding the idea of cosmologically distant quasars. One strong argument against them was that they implied energies that were far in excess of known energy conversion processes, including nuclear fusion. There were suggestions that quasars were made of some hitherto unknown form of stable antimatter regions and that this might account for their brightness. Others speculated that quasars were a white hole end of a wormhole, or a chain reaction of numerous supernovae.
Eventually, starting from about the 1970s, many lines of evidence (including the first X-ray space observatories, knowledge of black holes and modern models of cosmology) gradually demonstrated that the quasar redshifts are genuine and due to the expansion of space, that quasars are in fact as powerful and as distant as Schmidt and some other astronomers had suggested, and that their energy source is matter from an accretion disc falling onto a supermassive black hole. This included crucial evidence from optical and X-ray viewing of quasar host galaxies, finding of "intervening" absorption lines, which explained various spectral anomalies, observations from gravitational lensing, Peterson and Gunn's 1971 finding[citation needed] that galaxies containing quasars showed the same redshift as the quasars, and Kristian's 1973 finding that the "fuzzy" surrounding of many quasars was consistent with a less luminous host galaxy.
This model also fits well with other observations suggesting that many or even most galaxies have a massive central black hole. It would also explain why quasars are more common in the early universe: as a quasar draws matter from its accretion disc, there comes a point when there is less matter nearby, and energy production falls off or ceases, as the quasar becomes a more ordinary type of galaxy.
The accretion-disc energy-production mechanism was finally modeled in the 1970s, and black holes were also directly detected (including evidence showing that supermassive black holes could be found at the centers of our own and many other galaxies), which resolved the concern that quasars were too luminous to be a result of very distant objects or that a suitable mechanism could not be confirmed to exist in nature. By 1987 it was "well accepted" that this was the correct explanation for quasars, and the cosmological distance and energy output of quasars was accepted by almost all researchers.
Later it was found that not all quasars have strong radio emission; in fact only about 10% are "radio-loud". Hence the name "QSO" (quasi-stellar object) is used (in addition to "quasar") to refer to these objects, further categorised into the "radio-loud" and the "radio-quiet" classes. The discovery of the quasar had large implications for the field of astronomy in the 1960s, including drawing physics and astronomy closer together.
In 1979 the gravitational lens effect predicted by Albert Einstein's general theory of relativity was confirmed observationally for the first time with images of the double quasar 0957+561.
A study published in February, 2021, showed that there are more quasars in one direction (towards Hydra) than in the opposite direction, seemingly indicating that we are moving in that direction. But the direction of this dipole is about 28° away from the direction of our motion relative to the cosmic microwave background radiation.
In March, 2021, a collaboration of scientists, related to the Event Horizon Telescope, presented, for the first time, a polarized-based image of a black hole, particularly the black hole at the center of Messier 87, an elliptical galaxy approximately 55 million light-years away in the constellation Virgo, revealing the forces giving rise to quasars.
It is now known that quasars are distant but extremely luminous objects, so any light that reaches the Earth is redshifted due to the metric expansion of space.
Quasars inhabit the centers of active galaxies and are among the most luminous, powerful, and energetic objects known in the universe, emitting up to a thousand times the energy output of the Milky Way, which contains 200–400 billion stars. This radiation is emitted across the electromagnetic spectrum, almost uniformly, from X-rays to the far infrared with a peak in the ultraviolet optical bands, with some quasars also being strong sources of radio emission and of gamma-rays. With high-resolution imaging from ground-based telescopes and the Hubble Space Telescope, the "host galaxies" surrounding the quasars have been detected in some cases. These galaxies are normally too dim to be seen against the glare of the quasar, except with special techniques. Most quasars, with the exception of 3C 273, whose average apparent magnitude is 12.9, cannot be seen with small telescopes.
Quasars are believed—and in many cases confirmed—to be powered by accretion of material into supermassive black holes in the nuclei of distant galaxies, as suggested in 1964 by Edwin Salpeter and Yakov Zel'dovich. Light and other radiation cannot escape from within the event horizon of a black hole. The energy produced by a quasar is generated outside the black hole, by gravitational stresses and immense friction within the material nearest to the black hole, as it orbits and falls inward. The huge luminosity of quasars results from the accretion discs of central supermassive black holes, which can convert between 6% and 32% of the mass of an object into energy, compared to just 0.7% for the p–p chain nuclear fusion process that dominates the energy production in Sun-like stars. Central masses of 105 to 109 solar masses have been measured in quasars by using reverberation mapping. Several dozen nearby large galaxies, including our own Milky Way galaxy, that do not have an active center and do not show any activity similar to a quasar, are confirmed to contain a similar supermassive black hole in their nuclei (galactic center). Thus it is now thought that all large galaxies have a black hole of this kind, but only a small fraction have sufficient matter in the right kind of orbit at their center to become active and power radiation in such a way as to be seen as quasars.[43]
This also explains why quasars were more common in the early universe, as this energy production ends when the supermassive black hole consumes all of the gas and dust near it. This means that it is possible that most galaxies, including the Milky Way, have gone through an active stage, appearing as a quasar or some other class of active galaxy that depended on the black-hole mass and the accretion rate, and are now quiescent because they lack a supply of matter to feed into their central black holes to generate radiation.[43]
Quasars in interacting galaxies[44]
The matter accreting onto the black hole is unlikely to fall directly in, but will have some angular momentum around the black hole, which will cause the matter to collect into an accretion disc. Quasars may also be ignited or re-ignited when normal galaxies merge and the black hole is infused with a fresh source of matter. In fact, it has been suggested that a quasar could form when the Andromeda Galaxy collides with our own Milky Way galaxy in approximately 3–5 billion years.
In the 1980s, unified models were developed in which quasars were classified as a particular kind of active galaxy, and a consensus emerged that in many cases it is simply the viewing angle that distinguishes them from other active galaxies, such as blazars and radio galaxies.
The highest-redshift quasar known (as of December 2017) was ULAS J1342+0928, with a redshift of 7.54, which corresponds to a comoving distance of approximately 29.36 billion light-years from Earth (these distances are much larger than the distance light could travel in the universe's 13.8 billion year history because space itself has also been expanding).
More than 750000 quasars have been found (as of August 2020), most from the Sloan Digital Sky Survey. All observed quasar spectra have redshifts between 0.056 and 7.64 (as of 2021). Applying Hubble's law to these redshifts, it can be shown that they are between 600 million and 29.36 billion light-years away (in terms of comoving distance). Because of the great distances to the farthest quasars and the finite velocity of light, they and their surrounding space appear as they existed in the very early universe.
The power of quasars originates from supermassive black holes that are believed to exist at the core of most galaxies. The Doppler shifts of stars near the cores of galaxies indicate that they are revolving around tremendous masses with very steep gravity gradients, suggesting black holes.
Although quasars appear faint when viewed from Earth, they are visible from extreme distances, being the most luminous objects in the known universe. The brightest quasar in the sky is 3C 273 in the constellation of Virgo. It has an average apparent magnitude of 12.8 (bright enough to be seen through a medium-size amateur telescope), but it has an absolute magnitude of −26.7. From a distance of about 33 light-years, this object would shine in the sky about as brightly as our Sun. This quasar's luminosity is, therefore, about 4 trillion (4×1012) times that of the Sun, or about 100 times that of the total light of giant galaxies like the Milky Way. This assumes that the quasar is radiating energy in all directions, but the active galactic nucleus is believed to be radiating preferentially in the direction of its jet. In a universe containing hundreds of billions of galaxies, most of which had active nuclei billions of years ago but only seen today, it is statistically certain that thousands of energy jets should be pointed toward the Earth, some more directly than others. In many cases it is likely that the brighter the quasar, the more directly its jet is aimed at the Earth. Such quasars are called blazars.
The hyperluminous quasar APM 08279+5255 was, when discovered in 1998, given an absolute magnitude of −32.2. High-resolution imaging with the Hubble Space Telescope and the 10 m Keck Telescope revealed that this system is gravitationally lensed. A study of the gravitational lensing of this system suggests that the light emitted has been magnified by a factor of ~10. It is still substantially more luminous than nearby quasars such as 3C 273.
Quasars were much more common in the early universe than they are today. This discovery by Maarten Schmidt in 1967 was early strong evidence against steady-state cosmology and in favor of the Big Bang cosmology. Quasars show the locations where massive black holes are growing rapidly (by accretion). These black holes grow in step with the mass of stars in their host galaxy in a way not understood at present. One idea is that jets, radiation and winds created by the quasars shut down the formation of new stars in the host galaxy, a process called "feedback". The jets that produce strong radio emission in some quasars at the centers of clusters of galaxies are known to have enough power to prevent the hot gas in those clusters from cooling and falling on to the central galaxy.
Quasars' luminosities are variable, with time scales that range from months to hours. This means that quasars generate and emit their energy from a very small region, since each part of the quasar would have to be in contact with other parts on such a time scale as to allow the coordination of the luminosity variations. This would mean that a quasar varying on a time scale of a few weeks cannot be larger than a few light-weeks across. The emission of large amounts of power from a small region requires a power source far more efficient than the nuclear fusion that powers stars. The conversion of gravitational potential energy to radiation by infalling to a black hole converts between 6% and 32% of the mass to energy, compared to 0.7% for the conversion of mass to energy in a star like our Sun. It is the only process known that can produce such high power over a very long term. (Stellar explosions such as supernovas and gamma-ray bursts, and direct matter–antimatter annihilation, can also produce very high power output, but supernovae only last for days, and the universe does not appear to have had large amounts of antimatter at the relevant times.)
Since quasars exhibit all the properties common to other active galaxies such as Seyfert galaxies, the emission from quasars can be readily compared to those of smaller active galaxies powered by smaller supermassive black holes. To create a luminosity of 1040 watts (the typical brightness of a quasar), a super-massive black hole would have to consume the material equivalent of 10 stars per year. The brightest known quasars devour 1000 solar masses of material every year. The largest known is estimated to consume matter equivalent to 10 Earths per second. Quasar luminosities can vary considerably over time, depending on their surroundings. Since it is difficult to fuel quasars for many billions of years, after a quasar finishes accreting the surrounding gas and dust, it becomes an ordinary galaxy.
Radiation from quasars is partially "nonthermal" (i.e., not due to black-body radiation), and approximately 10% are observed to also have jets and lobes like those of radio galaxies that also carry significant (but poorly understood) amounts of energy in the form of particles moving at relativistic speeds. Extremely high energies might be explained by several mechanisms (see Fermi acceleration and Centrifugal mechanism of acceleration). Quasars can be detected over the entire observable electromagnetic spectrum, including radio, infrared, visible light, ultraviolet, X-ray and even gamma rays. Most quasars are brightest in their rest-frame ultraviolet wavelength of 121.6 nm Lyman-alpha emission line of hydrogen, but due to the tremendous redshifts of these sources, that peak luminosity has been observed as far to the red as 900.0 nm, in the near infrared. A minority of quasars show strong radio emission, which is generated by jets of matter moving close to the speed of light. When viewed downward, these appear as blazars and often have regions that seem to move away from the center faster than the speed of light (superluminal expansion). This is an optical illusion due to the properties of special relativity.
Quasar redshifts are measured from the strong spectral lines that dominate their visible and ultraviolet emission spectra. These lines are brighter than the continuous spectrum. They exhibit Doppler broadening corresponding to mean speed of several percent of the speed of light. Fast motions strongly indicate a large mass. Emission lines of hydrogen (mainly of the Lyman series and Balmer series), helium, carbon, magnesium, iron and oxygen are the brightest lines. The atoms emitting these lines range from neutral to highly ionized, leaving it highly charged. This wide range of ionization shows that the gas is highly irradiated by the quasar, not merely hot, and not by stars, which cannot produce such a wide range of ionization.
Like all (unobscured) active galaxies, quasars can be strong X-ray sources. Radio-loud quasars can also produce X-rays and gamma rays by inverse Compton scattering of lower-energy photons by the radio-emitting electrons in the jet.
Iron quasars show strong emission lines resulting from low-ionization iron (Fe II), such as IRAS 18508-7815.
Quasars also provide some clues as to the end of the Big Bang's reionization. The oldest known quasars (z = 6) display a Gunn–Peterson trough and have absorption regions in front of them indicating that the intergalactic medium at that time was neutral gas. More recent quasars show no absorption region, but rather their spectra contain a spiky area known as the Lyman-alpha forest; this indicates that the intergalactic medium has undergone reionization into plasma, and that neutral gas exists only in small clouds.
The intense production of ionizing ultraviolet radiation is also significant, as it would provide a mechanism for reionization to occur as galaxies form. Despite this, current theories suggest that quasars were not the primary source of reionization; the primary causes of reionization were probably the earliest generations of stars, known as Population III stars (possibly 70%), and dwarf galaxies (very early small high-energy galaxies) (possibly 30%).
Quasars show evidence of elements heavier than helium, indicating that galaxies underwent a massive phase of star formation, creating population III stars between the time of the Big Bang and the first observed quasars. Light from these stars may have been observed in 2005 using NASA's Spitzer Space Telescope, although this observation remains to be confirmed.
The taxonomy of quasars includes various subtypes representing subsets of the quasar population having distinct properties.
Radio-loud quasars are quasars with powerful jets that are strong sources of radio-wavelength emission. These make up about 10% of the overall quasar population. Radio-quiet quasars are those quasars lacking powerful jets, with relatively weaker radio emission than the radio-loud population. The majority of quasars (about 90%) are radio-quiet.
Broad absorption-line (BAL) quasars are quasars whose spectra exhibit broad absorption lines that are blueshifted relative to the quasar's rest frame, resulting from gas flowing outward from the active nucleus in the direction toward the observer. Broad absorption lines are found in about 10% of quasars, and BAL quasars are usually radio-quiet. In the rest-frame ultraviolet spectra of BAL quasars, broad absorption lines can be detected from ionized carbon, magnesium, silicon, nitrogen, and other elements.
Type 2 (or Type II) quasars are quasars in which the accretion disk and broad emission lines are highly obscured by dense gas and dust. They are higher-luminosity counterparts of Type 2 Seyfert galaxies.
Red quasars are quasars with optical colors that are redder than normal quasars, thought to be the result of moderate levels of dust extinction within the quasar host galaxy. Infrared surveys have demonstrated that red quasars make up a substantial fraction of the total quasar population.
Optically violent variable (OVV) quasars are radio-loud quasars in which the jet is directed toward the observer. Relativistic beaming of the jet emission results in strong and rapid variability of the quasar brightness. OVV quasars are also considered to be a type of blazar.
Weak emission line quasars are quasars having unusually faint emission lines in the ultraviolet/visible spectrum.
The energetic radiation of the quasar makes dark galaxies glow, helping astronomers to understand the obscure early stages of galaxy formation.
Because quasars are extremely distant, bright, and small in apparent size, they are useful reference points in establishing a measurement grid on the sky. The International Celestial Reference System (ICRS) is based on hundreds of extra-galactic radio sources, mostly quasars, distributed around the entire sky. Because they are so distant, they are apparently stationary to our current technology, yet their positions can be measured with the utmost accuracy by very-long-baseline interferometry (VLBI). The positions of most are known to 0.001 arcsecond or better, which is orders of magnitude more precise than the best optical measurements.
A grouping of two or more quasars on the sky can result from a chance alignment, where the quasars are not physically associated, from actual physical proximity, or from the effects of gravity bending the light of a single quasar into two or more images by gravitational lensing.
When two quasars appear to be very close to each other as seen from Earth (separated by a few arcseconds or less), they are commonly referred to as a "double quasar". When the two are also close together in space (i.e. observed to have similar redshifts), they are termed a "quasar pair", or as a "binary quasar" if they are close enough that their host galaxies are likely to be physically interacting.
As quasars are overall rare objects in the universe, the probability of three or more separate quasars being found near the same physical location is very low, and determining whether the system is closely separated physically requires significant observational effort. The first true triple quasar was found in 2007 by observations at the W. M. Keck Observatory Mauna Kea, Hawaii. LBQS 1429-008 (or QQQ J1432-0106) was first observed in 1989 and at the time was found to be a double quasar. When astronomers discovered the third member, they confirmed that the sources were separate and not the result of gravitational lensing. This triple quasar has a redshift of z = 2.076. The components are separated by an estimated 30–50 kiloparsecs (roughly 97,000-160,000 light years), which is typical for interacting galaxies. In 2013, the second true triplet of quasars, QQQ J1519+0627, was found with a redshift z = 1.51, the whole system fitting within a physical separation of 25 kpc (about 80,000 light years).
The first true quadruple quasar system was discovered in 2015 at a redshift z = 2.0412 and has an overall physical scale of about 200 kpc (roughly 650,000 light years).
A multiple-image quasar is a quasar whose light undergoes gravitational lensing, resulting in double, triple or quadruple images of the same quasar. The first such gravitational lens to be discovered was the double-imaged quasar Q0957+561 (or Twin Quasar) in 1979. An example of a triply lensed quasar is PG1115+08. Several quadruple-image quasars are known, including the Einstein Cross and the Cloverleaf Quasar, with the first such discoveries happening in the mid-1980s.
094253 Jack Reyes
Inspiration from banderitas and kites...kids to represent when creativity is at its peak
danielsolisblog.blogspot.com/2012/04/hierarchy-of-interfa...
Hierarchy of Interface for Tabletop Games as observed by John Stavropoulos
TOOLS
The actual components of play, like character sheets, cheat sheets, boards and bits.
TEXT
The actual documented rules and how they are presented, including exact wording, procedures and game terms.
RULES
The parameters of play as best recalled by the players. Less formal than text, but more formal than the basic design intent.
INTENT
The assumptions of how a game would be played, often expressed directly by the designer with minimal formal documentation.
Source:
“This is why I feel game interfaces (character sheets, cheat sheets) are more important than rules text and rules text is more important than rules and rules are more important than design intent when it comes to actual play... we generally can’t assume players will read the rules, that GMs won’t remember more than 5-7 distinct pieces of information at a time without reference, and if we don’t provide teaching tools, that the game will be taught correctly.”
plus.google.com/u/0/111266966448135449970/posts/aqxmnLe61rg
DESIGN: Daniel Solis — danielsolis.com
“Dice,” “Pencil” symbol from The Noun Project collection.
“Paper” symbol by Tom Schott, from The Noun Project collection.
“Quote” symbol by Henry Ryder, from The Noun Project collection.
“Note” symbol by Brendan Lynch, from the Noune Project collection.
“Pawn” symbol by Kenneth Von Alt, from The Noun Project collection.
“Dialog” symbol by Dima Yagnyuk, from The Noun Project collection.
had these old mattresses sitting outside my house, to be thrown away, and I knew I had to do something eccentric! Its almost the reverse of this photo shot from the window I was posing in. Instead though, it was much darker and had a sense of 'a fall' the construction overalls innocence, I am also doing a photo every week of the construction site and going to put them together! I'm VERY behind on putting them together, so I will have to spend a day doing that XD
Pics from various XML code just made up out of copied parts. Made it up to 400 nodes. Some were pre-auto adjusting node size.
Pics from various XML code just made up out of copied parts. Made it up to 400 nodes. Some were pre-auto adjusting node size.
I had to delete original and process scan again. It was just plain and gray.
My first BW film attempt after two years of digital.
091428
Monica Esquivel
I wanted to give the poster an artsy and organic feel, thus the many curves. The word "kalinangan" is related to culture, which I think Ateneo's is quite rich and diverse. I used black and gold to show this. The Ateneo art culture is also progressing, so, to show this growth, I used flowers.