PoS(FFP14)062 a us of http://pos.sissa.it/ ergies by SHALON xplosion of extragalactic ce. r Cherenkov telescopes as a well-known extragalactic object s cluster of . NGC 1275 yzed the SHALON data, we have SHALON Cherenkov telescope. energy distributions and images at ound NGC 1275 is evidence of the ray sources. In 1996, the SHALON ng-term observations of the he jets at the galactic center with the as possible candidates for the sources h energy gamma-ray emission coinci- eille ussia ussia ive Commons Attribution-NonCommercial-ShareAlike Licen -ray emission is generated by relativistic jets in the nucle -ray emission generated by various mechanisms. The Seyfert -ray emission from the two of nearby object - GK Per of classi- γ γ γ SW from NGC 1275 and the explosion of extragalactic supernov ◦ 3 ∼ ∗ 800 GeV for the first time. The results obtained at very high en > [email protected] [email protected] Cluster which are revealed the gas of the . Also, we present the results of lo Speaker. observations revealed a new metagalactic source of very hig interaction of cosmic rays and magnetic fields generated in t NGC 1275 has been observedpart by of the program SHALON of high-altitude long-term studies mirro of metagalactic gamma- dent in its coordinates with thedetermined such NGC 1275. characteristics of Having anal NGCenergies 1275 as the spectral are indicate that a partNGC of 1275 TeV itself, but the presence of an extended structure ar cal nova type, located at SN2006gy that is about 10supernova was minutes observed away at from TeV energies NGC for the 1275. first time So, with the e galaxy NGC 1275 is the central,is dominant known as galaxy a in powerful the source Perseu of radio and X-ray emission. The The cluster of galaxies in Perseus have long been considered of high and very high energy ∗ Copyright owned by the author(s) under the terms of the Creat c

Frontiers of Fundamental Physics 14 -15-18 FFP14, July 2014 Aix Marseille University (AMU) Saint-Charles Campus, Mars V.Y. Sinitsyna P.N. Lebedev Physical Institute, Leninsky pr. 53, Moscow, R V.G. Sinitsyna E-mail: E-mail: Very high energy gamma-emission of Perseus Cluster P.N. Lebedev Physical Institute, Leninsky pr. 53, Moscow, R PoS(FFP14)062 The (Fig. 1). right: 1 3, 22, 23]. laxies have − rage integral s V.G. Sinitsyna 09. 2 . − 0 ± ce detected in our cm . The observations ◦ 13 24 . -ray emission at very -rays and low-energy − 2 γ γ − 10 to 33 = N experiment. The color × NGC 1275 surrounded by ◦ elescope at energies above γ ) .2 h in different years (from k 5 . ns, which reveal shells of hot taining information about the 0 en searched for in the SHALON ± m detected signal for the energy ls describing them. Figure 3 left clusters owing to its relative prox- tic source of 8 o its close proximity to the Earth at . uster is NGC 1275 (Figs.1,2,3). es from 3 7 . In 1996, the observations with the of TeV gamma rays emitted by pro- e the mechanisms of the generation ics of relativistic jets. regions of TeV galactic wind or active galactic nuclei laxy NGC 1275 [14, 15, 16, 17, 18, 19, = ( le [10]. Evidence for the "feedback" role t interest owing to both its position at the ctures (Fig. 3) extending from the central, 8 TeV by SHALON. 1275 . 0 > NGC I 2 -ray-initiated showers in the same observing session [12, 1 γ confidence level determined according to Li&Ma [24]. The ave 100 Mpc or z = 0.0179) and brightness. Clusters of ga σ ∼ 4 800 GeV [14, 15] (Figs. 1, 2, 3). The position of emission sour . > Gamma-ray spectrum of NGC 1275 with a power-law index E Metagalactic sources of very high energy gamma-rays have be The cluster of galaxies in Perseus is one of the best-studied Figure 1 presents the source’s image at TeV energies by SHALO NGC 1275 is a powerful source of radio and X-ray emission. The image of the gamma-ray source NGC 1275 at energies Figure 1: left: high energies experiment coincides in its coordinates with20, the 21]. Seyfert NGC ga 1275 was1996 observed to by 2012) the during SHANON the telescope clear for moonless 271 nights at zenith angl NGC 1275 at very high energies imity (its distance experiment from the very beginningSHALON of mirror Cherenkov its telescope revealed operation a [12, new metagalac 13] were performed using thecosmic-ray standard background and for SHALON techniqueGamma-ray emission of from ob NGC 1275800 was GeV detected at by the the 31 SHALONflux t at energies above 800 GeV for NGC 1275 is scale in Fig. 1image right (in TeV). is Possible in correlations units between(radio the of and emission the X-ray) excess photons aboveof the should very minimu be high established energy to emission in elucidat the source and to test the mode Very high energy gamma-emission of Perseus Cluster Introduction long been considered as possibletons candidates and for electrons accelerated the at sources [1, large-scale 2, shocks 3, or 4, by 5, a 6, 7, 8, 9]. The dominantextended galaxy filamentary in structures the historically Perseus cl aroused grea center of the Perseus cluster and its possible "feedback" ro gas and cavities that spatially coincide with the radio stru of NGC 1275 can be obtained from ROSAT and Chandra observatio active part of the AGN. NGC 1275 also arouses interest owing t redshift z = 0.0179 [11], making it possible to study the phys PoS(FFP14)062 N ± n- 26 . 3 confidence d structure 5 keV) arc ) = ( . 3 40 TeV) and V.G. Sinitsyna σ 5 . − − GeV 5 8 . . nts a Chandra X-ray 800 > ( the center, known from data from the Fermi LAT I us cluster, on the whole, th an exponential cutoff, 7 keV [25] was also found. ); the contours represent the red on NGC 1275 with a size he X-ray emission disappears − ze of 32". The emission from 0.8 TeV at a 13 3 (at energies 1 . SHALON-1 (0 y identified the emission compo- gral flux adio and X-ray emission maxima [25]. A bright emission spot is also Integral spectrum of high and very high nts located in the north and the south ll correlates with the photon emission ation is that the intense emission from mponents of the extended double radio tinct maximum on NGC 1275 (Fig. 2). copes, and the scintillation Tibet Array. right: 3 40 TeV. -rays observed by SHALON from NGC 1275 have γ − 5 keV (Fig. 2). A correlation of the emission with energies . 5 keV) image of NGC 1275 [25]; the contours indicate the SHALO . 3 3 − − -ray energy spectrum of the central component in the entire e 5 5 γ . . . The 1 − s 2 5 keV X-ray) images. Figure 2 (black-and-white scale) prese − . -ray emission recorded by SHALON from NGC 1275 has an extende 3 γ cm Chandra X-ray (1 − 13 5 . − 5 keV) image for the central part of the Perseus cluster cente 10 -rays from NGC 1275 obtained by SHALON in comparison with the . 5 arcmin [25]. In the X-ray energy range, the core of the Perse γ . 3 40 TeV [17, 18, 19] and the X-ray emission in the range 0 × 5 The clearly seen dimming in X-ray flux, along with the dip NW of The emission regions of very high energy To analyze the emission related to this core, we additionall ) − − ∼ 5 . 30 8 . . of appears as a clear circularly symmetric structure with a dis the 1979 Einstein observations [26],structure correlates with 3C the 84 co (Fig.regions from 2). the north and These thethese dips south. rims are The comes simplest surrounded from interpret the byobserved shells bright to surrounding the the east. radio lobes 0 (1 Thus, the TeV a structure similar to that described above (see [25]) and we 0 image of NGC 1275 in theenergy energy range 800 GeV Chandra (1 regions in the energy range 1 with a distinct core centered at the source’s position. ergy range from 0.8 to 40 TeV is well described by a power law wi Figure 2: left: shows a ROSAT X-ray image of NGC 1275 (black-and-white scale satellite telescope, the MAGIC and VERITAS Cherenkov teles source’s radio structure fromcoincide VLA with radio the AGN observations. NGCalmost 1275 The completely (Figs. near r 2, the bright 3). areassymmetrically At of relative the the radio same to compone time, the t core [8]. We also combined the nent corresponding to thethe central central region region of of NGClevel NGC determined 1275 1275 by with was the a Li&Ma detected method si at [24] energies with above a average inte Very high energy gamma-emission of Perseus Cluster PoS(FFP14)062 . 1 − s 2 e’s − cm 13 represent −

10 V.G. Sinitsyna × ) 5 -ray emission from . γ 0 ± (see Fig. 2, the black 8 1 . − 7 kov telescope. s ( nd-based mirror Cherenkov m SHALON data (1996 - 2 − 11) [33] experimental data. cm ort-time (within five days) in- ) 11. The SHALON spectrum cor- 5 is represented in Fig. 2 by the . tions [33]. Figure 2 compares the servations with mirror Cherenkov average was recorded in 1999 and 0 ouds and haze and, in addition, the TeV ns in different energy ranges, com- ± , its evolution, and the emission gen- cate the upper limits from EGRET [29], es a continuous tracking of the source 20 TeV is described by a simple power d, dash-dotted, and dash-dotted with two 10 s nights, which already creates a gap in / 92 − . γ 1 8 ion of the flux changes remains necessary, E . − − ( GC 1275 obtained in the CM model [32]. -ray flux in the entire time of observations of = from zenith are needed, because the influence γ γ ◦ exp k 4 Spectral energy distribution of the × 10 . 0 ± right: 55 . 1 − 4 keV) image of NGC 1275 [8]. The contours represent the sourc E . 2 × − 13 1 . − , the spectral index is 10 γ k × E ) ∝ 11 . ) -ray flux variations, on average, do not exceed 20% of 0 γ ± TeV 8 ROSAT X-ray (0 and black triangle represent the data from the SHALON Cheren 92 . . 0 2 △ > -ray spectrum of NGC 1275 and its central region obtained fro 0 γ ) = ( E γ ( Recently, the AGN NGC 1275 was also recorded by the MAGIC grou Reliably revealing flares and their duration in long-term ob Nevertheless, revealing correlations between the emissio The observed E F > ( responding to the emission fromblack the triangles. central region of NGC 127 telescope at energies above 100 GeVintegral in the 2010 - 2011 observa NGC 1275. Given these variations, the flux decrease below the the Fermi LAT [27]; starsWhipple [30], are Magic and [28] VERITAS[31] datadots data. curves (see indicate the The the text). spectral arrows energy indi distributions The of dashe N 2012) with the Fermi LAT (2009 - 2011) [34] andVariability of MAGIC (2010 the - gamma-ray 20 emission from NGC 1275 telescopes is complicated by the factimpossible, that because the it technique requires mak such conditionsthe as data moonles for more thansource’s 10 passage days; at an a ideal atmosphere distance without of cl no more than 35 The SHALON mirror Cherenkovcreases telescope and has one detected decrease of three the sh very high energy I Figure 3: left: radio structure from VLA radio observations. NGC 1275. law of a change in atmospheric thickness should be minimal. paring the emission regions, and, in particular, the detect Very high energy gamma-emission of Perseus Cluster because it makes it possible to judge the nature of the source triangles). If the source’s spectrum in the energy range 0 eration mechanisms in various objects. PoS(FFP14)062 13 − -ray γ , with 10 γ k × -quantum E ) γ 5 . ∝ -ray flux for 7 ) γ V.G. Sinitsyna the O ± E 2 . bands: J band(1.25 > 8 TeV. The energy . ( 21 0 ( F center: > mn 2006. The detailed object. This object was and was constant during 1 er 2008 with a break for the − s o flux increase was found in 2 eriods of September, October, 8, to September 30, 2010 [34]. ber moonless period. After the power law − energy ranges, including those showed that the flux of SN2006 -ray fluxes by SHALON in the γ nalysis of 2007 have no revealed ase were found in 2001 and 2005, e times of the main flares observed , the flux increased about 6 times cm es by the Fermi LAT experiment. r 2010. In this time, only one e period of mid-October 2009 [34], se periods were 12 out 10 minutes away from NGC 1275. − nditions in both cases. , respectively. The duration of the flux 1 10 [37] at energies of − s × 1 2 ) − − s 2 17 [24] was determined. The integral . − cm . The increases were detected in late Jan. 2001, 0 σ 5 1 13 cm ± − − was detected in the period of October 18 - 20, 2009. s 12 2 -ray flux increase observed by SHALON. 1 10 69 − − γ . − -ray emission from SN2006 gy by SHALON telescope 0 × s 10 γ ( m) [35]. The SN2006gy by SHALON: 2 ) cm µ − × 5 . 13 ) 4 − cm 65 ± . 10 13 0 4 − . × ± ) 10 23 3 ( . 71 × . 1 ) 3 ( 5 ± . 7 , and 4 The SN2006gy image at TeV energy range. . 4 ± 13 ( 4 − m), and Ks band (2.2 . µ 10 right: 23 27 (fig. 4). An image of ( . × The image of SN2006 gy and the nucleus of NGC 1260 at three wave 0 ) -shower direction turned out the detection of metagalactic 4 ± γ . 12 13 . 3 ± 5 − . The flux increase was detected from the region NGC 1275 in autu To reveal possible correlations of the emissions in various Observations had been done in cloudless nights of moonless p = 35 m), H band (1.65 ( γ µ spectrum of SN2006 gy at 0.8 to 7 TeV can be approximated by the the November, December period. The results of observation a flux increase to These periods of SHALON observations do notat coincide Fermi with LAT [34]. th A slight localwhich flux corresponds increase to can the be above-mentioned seen in th SN2006 gy identified with the SN2006 gy [36] (fig. 4)that is ab SN 2006gy is found to be k is shown in Fig. 4.gy Follow-up had observations dropped on to end of a November flux level of about the integral flux was , Figure 4: left: integral spectrum; increase in October 2009 wasbecause 3 the days. observations No were intervals interrupted of due flux to weather incre co periods when the observationsThe were published simultaneous Fermi with LAT data theThe were on SHALON obtained observations from of August NGC 4, 1275Moon’s were 200 time, October performed 2009, in and Novemb mid-November-early Decembe analysis of November, December 2006 and thenSeptember during observations. the In winter the offrom flare, the 2007. NGC observed 1275 N on average Octoberstandard flux analysis, 22 and a excess stayed corresponding on to a this 6.2 level all Octo Very high energy gamma-emission of Perseus Cluster late Nov. early Dec. 2005, and late Oct. 2009. The fluxes in the at high and very high energies, we compared the NGC 1275 PoS(FFP14)062 , ◦ 5 h γ . 3 k 3 E GeV ∼ − . The ∝ 5 . σ ) O on region E esses. V.G. Sinitsyna > ( F The image of GK -rays in the observed -ray source associated γ right: γ . ntains the source of non- ) the observations of NGC xtragalactic supernova was o 8 . The 1 ignificance[24] of 9.2 source accompanying to NGC s with the central galaxy NGC ≥ − om 1996y to 2012y till now for s kov telescope. 2 e with similar flux and spectrum cal nova type as it located at or the effective field of view were by the power law spectrum of − and 2), as well as the flux variations of hot gas and cavities that spatially r the latter was obtained in ROSAT C 1275 at energies 800 GeV-40 TeV, ativistic jets from AGNs and for re- collection field of view relative to the he weak emission of shell, that is also cm al, active part of the AGN can be seen 13 − 10 × ) 3 , 6 1 ± 9 , 2 ) = ( 40 TeV by SHALON the contours indicate Chandra X-ray (1 TeV − 8 . -ray shower arrival direction revealed the main TeV-emissi 0 γ -ray source associated with the GK Per was detected above 800 > γ ( -ray emission in these regions is produced by a number of proc 35. The image of GK Per at TeV-energies by SHALON are shown wit . γ GKPer 0 I ± 90 Spectral energy distribution from GK Per obtained by SHALON -flux . γ 1 − = γ -ray emission from region of SN 2006gy. So, the explosion of e k γ As has been pointed out above, the Perseus cluster of galaxie During the observations of NGC 1275 the SHALON field of view co energy region from 2 to 15 TeV (Fig. 5, left) is well described 1275 is ideally suitablevealing both the for feedback studying role the ofand physics Chandra the of observations central rel at galaxy. low energies,coincide Evidence from with fo which the shells radio structures originating in the centr namely the images of the galaxysuggest and that its the surroundings TeV (Figs. 1 (Fig. 3, left and [8, 9, 25, 39]. The observational data for NG NGC 1275 as a point and extended source Per in the energy range 800 GeV thermal radio and X-ray emission GK Per (Nova 1901) of classi 1275 is naturally followed by1275 the was tracing observed of with GK SHALON Per.a telescope total during GK of the Per 111 period as hours. fr a The with the GK Persignal was significance detected for above this 800index SNR GeV obtained in is with the less a same observation then statisticalstandard hours because one procedure s of of for less SHALON the experiment.made sourc The to calculate corrections source f flux and energy spectrum.The energy with Fig. 5, right. The analysis of coinciding with the position of central sourceobserved of in GK X-ray Per by and Chandra t [38]. SW from NGC 1275. So due to the large telescopic field of view ( TeV GK Per (Nova 1901) Figure 5: left: keV) image of GK Per [38]. observed at TeV energies for the first time with SHALON Cheren with average Very high energy gamma-emission of Perseus Cluster PoS(FFP14)062 32” in ∼ V.G. Sinitsyna -rays are formed γ , L147 (1984). al nova type, located 10 ntral region of a SN2006gy that is about elescope in 1996 [14, 15, 32” around NGC 1275 are ly coincides with the X-ray 275, are being carried out in nverse Compton scattering of < ngles) and the short-time flux ctic supernova was observed at sible in TeV oduce synchrotron self-Compton pe. 75. The multifrequency spectral ted to the generation of an X-ray ear-long observations of the AGN ded structure around NGC 1275 is d very high energies, was described amely the images of the galaxy and ion as a result of the generation of c rays and magnetic fields generated ay-generating particles are swept up s generated in the jets at the galactic ray emission and the observed TeV the gas inside the Perseus cluster and GC 1275 nucleus (Fig. 3, the dashed, . G: Nucl. Phys. ilable Fermi LAT data at high energies he bubbles blown by the central black n is generated by relativistic jets in the TeV gamma-ray emission is generated term observations of the Perseus Cluster n by the central black hole in NGC 1275. ig. 3, the dash-dotted with two dots curve). ctrons (synchrotron self-Compton) of three 7 , 227 (1998). 9 , 529 (1999). , L93 (1980). 520 239 -ray emission from the two of nearby object - GK Per of classic γ SW from NGC 1275 and the explosion of extragalactic supernov ◦ 3 Long-term studies of the central galaxy in the cluster, NGC 1 The presence of emission in the energy range 1 - 40 TeV from a ce The extended structure around NGC 1275 (Fig. 2) that spatial ∼ at [4] C. L. Sarazin, Astrophys. J. References [1] B. Dennison, Astrophys. J. size around the nucleusvariability of point NGC to 1275 the (seejets origin Fig. ejected of by the 2, the very theenergy central high distribution black supermassive for energy the tria black emiss nucleus hole ofin NGC of 1275, the NGC up CM to 12 model high an [32]the and intrinsic is synchrotron a radiation composition fromseparate relativistic of ele the blobs ejected components from of thedash-dotted, i inner and regions dash-dotted of with the two N dotsand curves). The the ava SHALON observationsdescribed at in very terms high of energies thisemission in model of the with a relativistic one jets region from of the the nucleus itself components (F pr the SHALON experiment. We presentedNGC the 1275 results at of energies fifteen-y 80016, GeV 17, - 18, 40 19, TeV discovered 20]. byits The the surroundings, data SHALON obtained and t at the very fluxby high a variability energies, number indicate n of that processes: the nucleus in particular, of part NGC of 1275 this itself. emissio evidence Whereas, of the the presence interaction of of ancenter cosmic exten with rays the and gas of magnetic the field Perseus cluster. Also, in the long- 10 minutes away from NGCTeV 1275. energies for So, the first the time explosion with of SHALON extragala Cherenkov telesco [2] B. P. Houston, A. W. Wolfendale, and[3] E. C. M. S. Young, Colafrancesco J. and Phys P. Blasi, Astropart. Phys. Conclusion revealed the emission regions (Fig. 2)structure can [9, be produced 25, by 39].emission mechanisms shows rela The a sharp brightness increase distributionhole in of and intensity visible the right in outside X- the t from radio the band. region of This the suggests radioin that lobes the the under X-r the jets pressure at ofthrough cosmi the the center interaction of of very NGC highinterstellar energy 1275 gas cosmic heating [9, rays at the 39]. with boundary of the The bubbles blow structures vi Very high energy gamma-emission of Perseus Cluster PoS(FFP14)062 V.G. Sinitsyna , 352 (1999). , 409 (2003). 122 75A , 442 (2009). , 906 (2007). 196 , L65 (2000). , 391 (2004). , 417 (2006). , 209 (1995). 71 , L25 (1993). 318 417 366 , 788 (2000). , A82 (2010). 101 , L2 (2012). 264 356 , 29S (1992). 519 539 83 , 148 (2006). , 634A (2010). , 31 (2009). otchefstroom, 1997), p. 136. 644 , 47 (1981). , 1 (2011). 710 , 711 (2009). 699 n. Astrophys. 4 stron. Soc. , 2785 (2011). . 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