1 / 38

M77 (NGC 1068)

M77 (NGC 1068). By: Ryan Desautels. Messier 77. A Brief History General Information Galactic Information AGN Seyfert Research Question Does M77 have a barred structure? Does the brightness change, is it possible to detect this change? Summary. A Brief History. October 29 th , 1780;

javan
Télécharger la présentation

M77 (NGC 1068)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. M77 (NGC 1068) By: Ryan Desautels

  2. Messier 77 • A Brief History • General Information • Galactic Information • AGN • Seyfert • Research Question • Does M77 have a barred structure? • Does the brightness change, is it possible to detect this change? • Summary

  3. A Brief History • October 29th, 1780; • First observation made of NGC 1068 by M. Mechain. • He described it as a nebula • http://www.seds.org/messier/m/m077.html • December 17th, 1780; • Observed by Charles Messier and catalogued as “Cluster of faint stars, which contains nebulosity…” (Charles Messier, Catalogue). • http://www.kopernik.org/images/archive/m77.htm • Other notable early observations; • W. Hershel described M77 as a cluster of stars. • http://www.kopernik.org/images/archive/m77.htm • Rosse was the first astronomer to recognize M77 as a galaxy and not a star cluster. • http://www.kopernik.org/images/archive/m77.htm

  4. General Information • Type • What type of galaxy is Messier 77? • Size • What are some of the dimensions of Messier 77? • Brightness • What is the brightness of Messier 77 and some of its oddities?

  5. Type • NGC 1068 is a spiral galaxy (barred?). • Type Sb using Hubble’s Tuning Fork Diagram. • I will give an argument why this classification is no longer accurate. • Part of a group of galaxies known as Seyfert Galaxies. • Seyfert Galaxies are a subset of galaxies and other objects known as Active Galactic Nuclei (AGN). • M77 is the prototype galaxy for the Seyfert class.

  6. Bar or no bar? • Well, according to Gilbert A. Esquerdo and John C. Barentine, there is a barred structure present, at least in IR wavelengths. W N

  7. Bar in optical?

  8. Size • M77 is slightly larger then our own Milky Way. • M77 has an extent of roughly 170 000 light years with a core (brightest area) that makes up about 71% of it’s total size (120 000 light years). • It is at a distance of approximately 60 million light years.

  9. Size

  10. 120 000ly

  11. Brightness • Messier 77 has a brightness that varies (most observatories and papers classify the brightness somewhere in the range of 8.9 to 10.5). • Brightness variations is a property of Seyfert galaxies. Not only do they vary in brightness, they can also vary in class. • Messier 77 has a period of less then a week.

  12. Brightness • The core of M77 is very similar to that of a star (point source). Which is a property of Seyfert Galaxies.

  13. Active Galactic Nuclei (AGN) • A little background information on AGN’s • What are AGN’s • Are there different types of AGN’s, if so, what are they • Basic properties of AGN’s

  14. What are AGN’s • As a group, they are the most active galaxies out there. • Galaxies who’s nuclei alone produce more radiation then the rest of the galaxy. • The widely accepted model of an AGN galaxy is that it has a central super massive black hole as it’s engine.

  15. Different types of AGN’s • AGN’s are a general class of galaxies • Seyfert Galaxies • Type 1, and 2 • Radio Galaxies • Radio luminosity > 1033 W • Quasars • Very distant AGN’s • BL Lacertae Objects

  16. Basic properties of AGN’s • AGN’s as a group show all or most of the following characteristics. • High luminosity greater then 1037 W. • Nonthermal emission, with excessive UV, IR, Radio and X-Ray flux (compared to most galaxies). • Small region of rapid variability. • High contrast of brightness between nucleus and other structures (large scale). • Broad emission lines (sometimes).

  17. Seyfert Galaxies • First discovered by Carl K. Seyfert. • Messier 77 is the prototype Seyfert Galaxy. • What are Seyfert Galaxies? • What are the different types? • Type: 1,1.5,2 • What do different Seyfert galaxies share in common. • How is M77 a Seyfert Galaxy.

  18. Carl K. Seyfert • Pioneered research on nuclear emission in spiral galaxies. • 1943 he published a paper on galaxies with bright nuclei that exhibit characteristically broadened emission lines. • While at Warner Swasey Observatory and the Case Institute, he obtained the first good colour photographs of nebulae and stellar spectra. • Involved in instrumental innovations which included the use of photomultiplier tubes and television techniques in astronomy, and electronically controlled telescope drives.

  19. Different Types of Seyfert Galaxies • There are two different types of Seyfert Galaxies. NGC 5548 M77 Type 1 Type 2

  20. Type 1 • Type 1 galaxies have two sets of emission lines in their spectra: • Narrow lines, with widths of several hundred km/s • Broad lines, with widths of up to 104 km/s

  21. Type 2 • Object has only narrow lines present.

  22. Why different types • Types 1 and 2 are only different because of our point of view. It is thought that the differences are due to a torus which is preventing us from seeing the broad regions in Seyfert 2 galaxies.

  23. Messier 77’s variability • Is it possible to detect the variability? • If it is possible, what is the range in apparent magnitude?

  24. Variability • To find the variability: • Measure each individual object image. • Set the mean value of each object image ~ 0 • Measure the FWHM of a non-variable star in the field. • Measure an area around the star . • ~ 4x FWHM. • Adjust each image so that the star brightness (mean value) is the same in each object image.

  25. Variability • Measure the FWHM of the galaxy. • Measure an area around the core of the galaxy. • ~ 4x FWHM • Using the formula: • m-n = (2.5)log(Fn/Fm), • Where m-n = the change in brightness, • Fn = the mean value of the star, • Fm = the mean value of the galaxy.

  26. Variability

  27. Variability

  28. Variability

  29. Variability

  30. Variability

  31. Variability • We can see from the previous graph that there is some variability. • There is a change in variability of 0.07. • This change is quite small, however; it is greater then the error so I can say that there is definitely a change in brightness.

  32. Summary • Messier 77 is a Sb Type 2 Seyfert Galaxy. • It satisfies some of the criterion of the AGN model.

  33. Summary • Small region of rapid variability. • Yes, as shown in my graph the brightness does change, and the period of M77 is roughly 1 week. • http://www.kopernik.org/images/archive/m77.htm

  34. Summary • High contrast of brightness between nucleus and other structures (large scale). • Yes, it is only with special filters (Digital Development Processing DDP), that we are able to make out the central bulge area and the rest of the galaxy.

  35. Summary • Messier 77 is a galaxy who’s core has an almost stellar output.

  36. References • Images: • http://www.aao.gov.au/images/captions/aatccd012.html • http://archive.stsci.edu/cgi-bin/dss_form?target=m77&resolver=SIMBAD • http://cas.sdss.org/dr3/en/proj/advanced/galaxies/tuningfork.asp • http://www.noao.edu/outreach/aop/observers/m77.html • http://nedwww.ipac.caltech.edu/cgi-bin/nph-imgdata?objid=58240&objname=MESSIER%20077 • http://www.astrosurf.com/astroduvel/images/m77.html • Information: • http://imagine.gsfc.nasa.gov/docs/science/know_l1/active_galaxies.html • http://www.astr.ua.edu/keel/agn/ • http://www.noao.edu/outreach/aop/observers/m77.html • http://coolcosmos.ipac.caltech.edu/cosmic_classroom/multiwavelength_astronomy/multiwavelength_museum/m77.html • http://seds.lpl.arizona.edu/messier/more/m077_hst.html • http://www.messiermarathon.com/new_page_83.htm • Introductory Astronomy & Astrophysics 4th E., 1998 • http://www.ne.jp/asahi/stellar/scenes/object_e/m77.htm

More Related