09/04/2013

Kelvin Au

PHYS 2070 FINAL PROJECT

NGC 6503

• Morphological Type: SA(s)cd

• Right Ascension (J2000): 17hr. 49min. 26.514sec.

• Declination (J2000): +70deg. 08' 39.63“

• Size: 4.7’ x 1.5’

• Physical Size (Diameter) (ly): 56317.5

• Visual (Apparent) Magnitude: 10.83

• Visual (Absolute) Magnitude: -18.82

• Surface Brightness (m ”-2): 21.6

Aladin, SIMBAD, VizieR, Starry Night Planetarium Software

Starry Night Planetarium Software

InfraredIRAS Survey: 100

OpticalDigitized Sky Survey

Radio0408 MHz: HI All-Sky

Continuum Survey

X-RayHEAO 1A

X-RayRASS Broad

OrientationUp – NorthLeft – East

Image Credit: SkyView

DATA & OBSERVATIONS

• Date: February 12/13, 2013

• Image Capture Time: 22:43 CST

• Temperature: -9°C

• Seeing: Excellent

• Cloud Cover: 5%

• Sky Glow 1/5

• Transparency: Excellent

• FWHM of Focus Star: 4-6 px.

• Moon Phase: Waxing Crescent

• Moonrise: 08:21:23 CST

• Moonset: 21:08:59 CST

• Sunrise: 07:43 CST

• Sunset: 17:42 CST

• SQM: 20.05, 20.03, 20.12

• Focus Displayed: 242

• FWHM of Target 2-11

OBSERVATION CONDITIONS

IMAGE PROCESSING

• Master Bias

• Master Dark

• Master Flat

• Reducing the Image

• Had to split into 3 substacks

• Ended up using 24 frames

• Final Image

Bias

Dark

Flat

499 x 426 pixels

OrientationDown – NorthLeft – East

16 Colour LUT

Log Up LUT & Negative

OrientationDown – NorthLeft – East

CURRENT RESEARCH & KNOWLEDGE

BACKGROUND• The problem with Rotation Curves…

• Maximum Disc Hypothesis

• Influence of Dark Matter

Image Adapted: PhilHibbs, Wikipedia Commons

(Binney et al. 1998)

• ‘The maximum rotation of a galactic disc’ (Bottema 1997)

• Find quantity of dark matter contained in a galaxy

• Assumptions made

• Model formulated

• Apply to NGC 6503 & NGC 1560

• NGC 6503 being a normal sized galaxy with normal surface brightness

RESEARCH PAPER

(Bottema 1997)

Image Adapted: (Bottema 1997)

FOCUS AREA

CALCULATE THE DISTANCE TO NGC 6503!

(This was way more involved than I was hoping for!)

• Use Distance Modulus to find the Distance

• Need Apparent Magnitude

• Image Measurements

• Need Absolute Magnitude

• Tully-Fisher Relation

Find Apparent Magnitude of Galaxy

• Used contour to find the flux count

OrientationDown – NorthLeft – East

Gaussian Blur: 5px.

Find Apparent Magnitude of Galaxy

• Used contour to find the flux count

• Compare magnitude to count of known star for scale

Image Credit: ALADIN

Find Apparent Magnitude of Galaxy

• Used contour to find the flux count

• Compare magnitude to count of known star for scale

• Apparent magnitude formula

Galaxy: F1=1847180

Comparison Star: F2 = 26605.3376, m2 = 14.819

Apparent magnitude: m = 10.08

(VizierR, SIMBAD)

CompareB Band: 10.90J Band: 8.201

(This is slightly reassuring!)

Find Absolute Magnitude of Galaxy

• Tully-Fisher Relation

(Binney et al. 1998, Rhee et al. 2005)

Find Absolute Magnitude of Galaxy

• Tully-Fisher Relation

Remember the value as obtained from Rhee et al.’s paper

(Rhee et al. 2005)

Finally Assembling the Pieces

• Can’t use the apparent magnitude (10.08) that was measured

Remember the value as obtained from Rhee et al.’s paper

d = 6.76 Mpc.

d = 7.32 Mpc.

d = 8.09 Mpc.

(Rhee et al. 2005)

Finally Assembling the Pieces

• Can’t use the apparent magnitude (10.08) that was measured

• Compare

Literature Values

Rhee et al. (2005): 4.4 Mpc.

Bottema (1997): 6.0 Mpc.

Starry Night: 8.55 Mpc.

Calculated Values

iflat: 6.76 Mpc.

imax: 7.32 Mpc.

Rhee et al. (2005): 8.09 Mpc.

Starry Night Values: 8.09 Mpc.

FINAL REMARKS

• The whole apparent magnitude determination was basically pointless

• At least it seemed correct

• Final distance values – not bad

• Error! So much error!

• Way more work than I hoped for…

• But I learned a lot… (I guess…)

CITATIONS

Binney J, Merrifield M. 1998. Relative Distance Estimators. In Galactic Astronomy, Princeton University Press. Princeton. 796pp.

Bottema R. 1997. The maximum rotation of a galactic disc. 328:517-525. arXiv:astro-ph/970623v1.

http://arxiv.org/abs/astro-ph/9706230v1

Rhee M, Broeils A. 2005. HI LINEWIDTHS, ROTATION VELOCITIES AND THE TULLY-FISHER RELATION. Journal of Astronomy and Space Sciences.

22:2:89-112.http://koreascience.or.kr/article/ArticleFullRecord.jsp?cn=OJOOBS_2005

_v22n2_89

CITATIONS

SIMBAD Astronomical Database. http://simbad.u-strasbg.fr/simbad/

VizieR Service.http://vizier.u-strasbg.fr/viz-bin/VizieR

SkyView. National Aeronautics and Space Administration.http://skyview.gsfc.nasa.gov/

Aladin Sky Atlas.http://aladin.u-strasbg.fr/aladin.gml

PhilHibbs. GalacticRotation2.svg http://en.wikipedia.org/wiki/File:GalacticRotation2.svg

Starry Night planetarium software and ImageJ image software were used.