David's Astronomy Pages (Stellar & Deep Sky)
Active Galactic Nuclei (AGNs)

Bullet Introduction This page summarises observations and images of active galactic nuclei objects (AGNs)
Bullet BL Lac - Active Extragalactic Object (Blazer)
Bullet NGC 1275 - Seyfert Galaxy
Bullet NGC 2782 - Spiral Galaxy (Seyfert type)
Bullet NGC 4151 - Spiral Galaxy (Seyfert Galaxy)
Bullet NGC 7674 - Type II Seyfert
Bullet M77 - Type II Seyfert
Bullet Double Quasar Q0957+561 - Gravitationally Lensed Quasar
Bullet 3C 110 - Quasar
Bullet 3C 273 - Quasar

 


Introduction - AGNs

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 - Active Extragalactic Object (Blazer),  BL Lac type variable

BL Lac (Lacerta)

Image

CCD Image 
120 sec exposure, 2x2 binning, R Filter
2006-12-02 18:06h UT (#157058)
  
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 ]

Image

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
Image 
  
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.
Image 
   
BL Lac Magnitude Variation -  August to Early October 2007
Dataset comprising observations from 16 nights between 2007-08-08 and 2007-10-05
Image 
   
BL Lac - Magnitude Variation - Dec 2006 
Dataset comprising observations from 16 nights between 2006-11-26 and 2006-12-25
Image 

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NGC 1275 - Seyfert Galaxy

NGC 1275 (Perseus)
Part of Perseus A / Abell 426

Image
  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 - Spiral Galaxy (Seyfert Type)

NGC 2782 (Lynx)

 Image

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
 Image
Annotated CCD Image 
120s exposure, 2x2 binning, C filter,  
2007-03-15  23:36h UT (#183268)
 
NGC 2782 - Magnitude Variation  
Image 

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NGC 4151 - Spiral Galaxy (Seyfet Galaxy)

NGC 4151 (Canes Venatici)
bright star to right is 8th mag star HIP 59295, 
smaller spiral galaxy to top left is NGC 4156

Image
CCD Image
5 x 180s exposure (average combine), 2x2 binning, C Filter
2006-12-20 03:42h UT (#167438-42)

 

NGC 4151 - potential reference stars

Image
Annotated CCD Image
60s exposure, 2x2 binning, V Filter
2006-12-20 03:55h UT (#167448)
 
Photometric Monitoring of NGC 4151
Image
Image

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NGC 7674 - Type II Seyfert 

NGC 7674 (Pegasus)

Image

Annotated CCD Image 
3 x 3 min exposure (average combine), 2x2 binning, C Filter
2006-12-08 20:32h UT (#160128-32)

 

NGC 7674 in R Filter

Image

Annotated CCD Image 
120 sec exposure, 2x2 binning, R Filter
2006-12-08 20:28h UT (#160129)

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M77 - Type II Seyfert

M77 (Cetus)

Image 
 CCD Image 
9 x 2 min (average combine), clear filter
2005-12-21 21:25h UT (#107044-52)
 
M77 Galaxy (enhanced)
 Image
A
Image
B
 Image
C
Image
D
2002-09-01  01:12 to 01:18h UT
Enhanced CCD Image, 11 x 30 sec exposure
 (#22102-12)

A. Sum Combine 11 frames
B. Richardson-Lucy  Sharpening
C. Mid Range Brightening 
D. False Colour Combination of A-C

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Double Quasar Q0957+561  (Gravitationally Lensed Quasar)

 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 ]
Image
 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)

Quasar Q0957+561 

Image   Image

Location wrt NGC 3079

 CCD Image
3 x 2 min exposure (average combine), 2x2 binning, C Filter 
2006-02-10 20:49h UT (#114097-99)
  
 Quasar Q0957+561 A/B 
Image
 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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3C 110 - Quasar

Quasar 3C 110 (Eridanus)

Image
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 - Quasar

3C 273 (Virgo) 
Quasar 1.9 billion light years distance from Solar System
Image 
CCD Image, 
3 x 60s (median combine), clear filter
2005-05-13  22:49 h UT (#86127-30)

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