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Active Galactic Nuclei (AGNs)
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An active galactic nucleus (AGN) is a compact region at the
centre of a galaxy which has a much higher than normal luminosity over some or
all of the electromagnetic spectrum (in the radio, infrared, optical,
ultra-violet, X-ray and/or gamma ray wavebands). A galaxy hosting an AGN is
called an active galaxy. The radiation from AGN is believed to be a result of
accretion on to the supermassive black hole at the centre of the host
galaxy.
AGN are frequently divided into two classes, conventionally called radio-quiet
and radio-loud. AGN terminology is often confusing, since the distinctions
between different types of AGN sometimes reflects historical differences in how
objects were discovered or initially classified, rather than real physical
differences.
Some types of AGN that I've acquired images of are listed below
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BL Lac (Lacerta) |
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CCD Image 120 sec exposure, 2x2 binning, R Filter 2006-12-02 18:06h UT (#157058) |
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BL Lac monitoring Reference image shown below. (reference stars: C2 and C12, check stars : K20,K25). Calculated magnitude of BL Lac +13.74 (R). [Reference magnitude data for stars C2 and C12 from OPTICAL AND NEAR-INFRARED CALIBRATION OF AGN FIELD STARS by GONZÁLEZ-PÉREZ et al, The Astronomical Journal, volume 122 (2001), large size reference picture ] |
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CCD Image 3 x 120 sec exposure (median combine), 2x2 binning, R Filter 2006-11-26 20:24h UT (#155116-18) |
| BL Lac - Magnitude Variation - Late 2006 to 2009 |
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| BL Lac Magnitude
Variation - Nov 2007 to March 2008 Dataset comprising observations from 32 nights between 2007-11-15 and 2008-03-12 Note 0.5 mag brightening between 2008-02-19 & 2008-02-24, which seems to have lasted for 4-7 days. |
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| BL Lac Magnitude
Variation - August to Early October 2007 Dataset comprising observations from 16 nights between 2007-08-08 and 2007-10-05 |
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| BL Lac - Magnitude
Variation - Dec 2006 Dataset comprising observations from 16 nights between 2006-11-26 and 2006-12-25 |
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| BL Lac (Lacerta) AT2021bag (Type: BL) outburst of BL Lac discovered 2021/01/21.654 UT by Gaia Alias: Gaia21akj, BL Lac | Gaia21akj | |
| AT2021bag - 2021-01-25 (T+4.1d) Image below (2021-01-25.776) was taken 4.1 days after reported discovery 2021bag BL Lac is shown by white cross hairs. Measured magnitude +12.1 (vs catalog mag of +14.5) |
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| Annotated CCD Image (100% size, linear scale, cropped) 3 x 180s exposure (average combine), 3x3 binning, C Filter 2021-01-25 18:43 UT (#855005-07) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
| AT2021bag - 2021-11-28 (T+311.2d) Image below (2021-11-28.818) was taken 311.2 days after reported discovery 2021bag BL Lac is shown by white cross hairs. Measured magnitude +13.2 (vs catalog mag of +14.5) Object is noticeably dimmer than it was in image taken 2021-01-25 (T+4.1d) |
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| Annotated CCD Image (100% size, linear scale, cropped) 180s exposure (single frame), 3x3 binning, C Filter 2021-11-28 19:41 UT (#938013) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
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NGC 1275 (Perseus) |
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| Annotated CCD Image (50% size) 8 x 2 min (average combine), 1x1 binning, clear filter 2005-12-21 23:41h UT (#107218-25) |
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NGC 2782 (Lynx) |
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Annotated CCD Image 3 x 120s exposure (average combine), 2x2 binning, C filter, 2007-03-15 23:39h UT (#183267-71) |
| NGC 2782 & reference stars |
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Annotated CCD Image 120s exposure, 2x2 binning, C filter, 2007-03-15 23:36h UT (#183268) |
| NGC 2782 - Magnitude Variation |
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NGC 4151 (Canes Venatici) |
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| CCD Image 5 x 180s exposure (average combine), 2x2 binning, C Filter 2006-12-20 03:42h UT (#167438-42) |
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NGC 4151 - potential reference stars |
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| Annotated CCD Image 60s exposure, 2x2 binning, V Filter 2006-12-20 03:55h UT (#167448) |
| Photometric Monitoring of NGC 4151 |
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NGC 7674 (Pegasus) |
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Annotated CCD Image 3 x 3 min exposure (average combine), 2x2 binning, C Filter 2006-12-08 20:32h UT (#160128-32) |
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NGC 7674 in R Filter |
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Annotated CCD Image 120 sec exposure, 2x2 binning, R Filter 2006-12-08 20:28h UT (#160129) |
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M77 (Cetus) |
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| CCD Image 9 x 2 min (average combine), clear filter 2005-12-21 21:25h UT (#107044-52) |
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| Quasar Q0957+561
A/B (Ursa Major) Gravitationally lensed quasar 8.5 billion light years distance The pair of quasar images are around magnitude +17 and have a separation of about 6 arc secs. [ Other Internet Info/pics on Q0957+561 : 1, 2 , 3 , 4, 5 ] |
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| CCD Image - 250%
scaling, cropped & annotated 3 x 2 min exposure (average combine), 2x2 binning, C Filter 2006-02-10 20:49h UT (#114097-99) |
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Quasar Q0957+561 |
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Location wrt NGC 3079 |
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| CCD Image 3 x 2 min exposure (average combine), 2x2 binning, C Filter 2006-02-10 20:49h UT (#114097-99) |
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| Quasar Q0957+561 A/B | ||
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| CCD Image 5 x 2 min exposure (average combine), 1x1 binning, C Filter 2006-02-10 22:19h UT (#114148-52) |
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Quasar 3C 110 (Eridanus) |
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| CCD Image 3 x 120s exposure (average combine), 2x2 binning, C Filter 2006-12-16 23:43 hUT (#164367-69) |
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| 3C 273 (Virgo) Quasar 1.9 billion light years distance from Solar System |
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CCD Image, 3 x 60s (median combine), clear filter 2005-05-13 22:49 h UT (#86127-30) |
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| AT2021bgi (Canes Venatici) In 2MASX J12303540+4257559 AT2021bgi (Type AGN, zhost=0.065590) discovered 2021/01/27.048 UT by GSNST Alias: GSNST-21ar ( Rochester Supernova site ) |
| 2MASX J12303540+4257559 with AT2021bgi Galaxy with transient is shown by white cross hairs. Other galaxies in same field of view : PGC 41314 (catalog mag +16.5), PGC 2208351 (catalog mag +17.2) |
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| Annotated CCD Image (50% size, square root scale) 2 x 180s exposure (average combine), 3x3 binning, C Filter 2021-02-02 02:05 UT (#857263-66) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
| 2MASX J12303540+4257559 with AT2021bgi - 2021-02-02 (T+6.0d) Image below (2021-02-02.079) was taken 6.0 days after discovery of 2021bgi Transient/Galaxy nucleus is shown by white cross hairs. Combined magnitude +15.8 |
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| Annotated CCD Image (125% size, square root scale, cropped) 2 x 180s exposure (average combine), 3x3 binning, C Filter 2021-02-02 02:05 UT (#857263-66) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
| Images of AT 2021bg (2MASX J12303540+4257559) on Transients 2021 Page >> |
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| NGC 4151 with AT2021baf (Canes Venatici) AT2021baf (Type: AGN) discovered 2021/01/22.151 UT by Gaia Alias: Gaia21aki (Gaia alert came when AGN reached mag +12.2) ( Gaia21aki ) |
| NGC 4151, Seyfet Galaxy - 2021-02-02 (T+11.0d) Image below (2021-02-02.156) was taken 11.0 days after discovery of 2021baf Measured magnitude +11.8 (nucleus) |
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| CCD Image (100% size, square root scale, cropped) 4 x 180s exposure (average combine), 3x3 binning, C Filter 2021-02-02 03:52 UT (#857276-79) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
| NGC 4151, Seyfet Galaxy - 2021-01-26 (T+3.9d) Image below (2021-01-26.084) was taken 3.9 days after discovery of 2021baf Measured magnitude +11.7 (nucleus) |
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| CCD Image (100% size, square root scale, cropped) 4 x 180s exposure (average combine), 3x3 binning, C Filter 2021-01-26 02:11 UT (#855187-91) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
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| Negative CCD Image (100% size, square root scale, cropped) Image details as above |
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| CCD Image (100% size, log scale, cropped) Image details as above |
| NGC 4151 - Earlier Image (2021-01-24, T+2.0d) Image below (2021-01-24.175) was taken 2.0 days after reported AGN 2021baf Measured magnitude +11.6 (nucleus) |
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| CCD Image (100% size, square root scale, cropped) 4 x 180s exposure (average combine), 3x3 binning, C Filter 2021-01-24 04:20 UT (#854372-75) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
| NGC 4151 - Earlier Wider View Image (2021-01-24) with surrounding objects of interest Galaxy NGC 4156, bright star HIP 59295 (mag +8.1) and variable star AZ Cvn |
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| CCD Image (50% size, square root scale, cropped) 4 x 180s exposure (average combine), 3x3 binning, C Filter 2021-01-24 04:20 UT (#854372-75) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
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| AT2021eio (Ursa Major) AT2021eio (Type: QSO) discovered 2021/03/03.304 UT by Gaia Alias: Gaia21bel (alert mag +16.44 vs historic mag +16.66) ( Rochester Supernova site | Gaia21bel page ) |
| AT2021eio / VV2006, J091625.4+471442 QSO is shown by white cross hairs. |
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| Annotated CCD Image (50% size, square root scale, cropped) 5 x 180s exposure (average combine), 3x3 binning, C Filter 2021-04-01 21:17 UT (#879023-27) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
| AT2021eio / - 2021-04-01 (T+29.6d) Image below (2021-04-01.881) was taken 29.6 days after reported discovery of 2021eio QSO is shown by white cross hairs. Measured Magnitude +16.0 |
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| Annotated CCD Image (50% size, square root scale, cropped) 5 x 180s exposure (average combine), 3x3 binning, C Filter 2021-04-01 21:17 UT (#879023-27) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
| AT2021eio - 2022-01-22 (T+324.8d) Image below (2022-01-22.129) was taken 324.8 days after reported discovery of 2021eio QSO is shown by white cross hairs. Measured Magnitude +16.05 |
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| Annotated CCD Image (100% size, square root scale, cropped) 4 x 180s exposure (average combine), 3x3 binning, C Filter 2022-01-22 03:14 UT (#957324-27) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2 |
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| This Web Page: | Active Galactic Nuclei (AGNs) |
| Last Updated : | 2022-06-08 |
| Site Owner : | David Richards |
| Home Page : | David's Astronomy Web Site |
