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master's thesis
Proučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara
Zagreb: University of Zagreb, Faculty of Science, 2015. urn:nbn:hr:217:694269
Ceraj, Lana
University of Zagreb
Faculty of Science
Department of Physics

Institutional repository: Repository of the Faculty of Science

Cite this document

Ceraj, L. (2015). Proučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara (Master's thesis). Zagreb: University of Zagreb, Faculty of Science. Retrieved from https://urn.nsk.hr/urn:nbn:hr:217:694269

Ceraj, Lana. "Proučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara." Master's thesis, University of Zagreb, Faculty of Science, 2015. https://urn.nsk.hr/urn:nbn:hr:217:694269

Ceraj, Lana. "Proučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara." Master's thesis, University of Zagreb, Faculty of Science, 2015. https://urn.nsk.hr/urn:nbn:hr:217:694269

Ceraj, L. (2015). 'Proučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara', Master's thesis, University of Zagreb, Faculty of Science, accessed 19 December 2024, https://urn.nsk.hr/urn:nbn:hr:217:694269

Ceraj L. Proučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara [Master's thesis]. Zagreb: University of Zagreb, Faculty of Science; 2015 [cited 2024 December 19] Available at: https://urn.nsk.hr/urn:nbn:hr:217:694269

L. Ceraj, "Proučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara", Master's thesis, University of Zagreb, Faculty of Science, Zagreb, 2015. Available at: https://urn.nsk.hr/urn:nbn:hr:217:694269

Metadata
TitleProučavanje plina neutralnog vodika u dalekim galaksijama koristeći metodu slaganja spektara
Title (english)Studies of neutral hydrogen gas in distant galaxies using the spectral stacking technique
AuthorLana Ceraj
MentorVernesa Smolčić (mentor)
Committee memberVernesa Smolčić (predsjednik povjerenstva)
Committee memberMirko Planinić (član povjerenstva)
Committee memberIvica Smolić (član povjerenstva)
Committee memberKrešimir Pavlovski (član povjerenstva)
Committee memberKrešimir Kumerički (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Science
(Department of Physics)
Zagreb
Defense date and country2015-09-25, Croatia
Scientific / art field,
discipline and subdiscipline		NATURAL SCIENCES
Physics
Astronomy and Astrophysics
Abstract
Plin neutralnog vodika (HI) smatra se građevnom jedinicom galaksija jer služi kao primarno gorivo za stvaranje zvijezda. Izravna opažanja HI emisijske linije na 21 cm ograničena su granicama osjetljivosti radio teleskopa. Kako bi nadišli ovaj problem, koristimo relativno novu metodu slaganja spektara kako bi pomaknuli granice crvenih pomaka u radio opažanjima dalje nego li je moguće ostalim opažačkim metodama. U ovom radu predstavljena je statistička metoda slaganja HI spektara galaksija lociranih u tzv. G09 nebeskom polju, u rasponu crvenih pomaka 0.039<z<0.134. HI opažanja smiljena su Parkes radio teleskopom (New South Wales, Australija). Položaji galaksija i crveni pomaci nalaze se u katalogu dobavljenom iz baze podataka Galaxy and Mass Assembly (GAMA) istraživanja. Slažući spektre 7049 galaksija, ekstrahirane iz Parkes podatkovne kocke, postižemo dobar omjer signala i šuma, S/N=11.9. Šum pokazuje karakteristike Gaussiana, uz malo odstupanje zbog prisutnosti rezidualne radio-frekventne interferencije i emisije od snažnih izvora u podacima. Usrednjene veličine karakteristične HI dobivamo integrirajući složene spektre u granicama ±300 kms^−1 od sustava mirovanja. Taj raspon odgovara iznosu najveće očekivane širine HI profila. Srednja vrijednost gustoće toka, usrednjena masa HI i usrednjeni omjer mase i luminoziteta HI su (tim redoslijedom): (S)=(1.07±0.09)mJy, (M_HI)=(2.97±0.38)×10^9ℎ^−2M_⊙ i M_HI/L_r)=(1.58±0.39) M_⊙L_⊙^−1. Pri izračunu kozmičke gustoće mase HI (Ω_HI) testiramo dvije formule. Kako bi u izračun uključili i efekt konfuzije, koristimo faktor konfuzije.
Abstract (english)
Neutral hydrogen gas (HI) is the building block of galaxies as it is a primary fuel for star formation. Direct observations of the HI 21 cm emission line are restricted by the limited sensitivities of radio telescopes. To overcome this issue, we employ the relatively new technique of spectral stacking to push the redshift limits of radio observations further than otherwise possible. This thesis presents an HI spectral stacking analysis of galaxies within the Galaxy and Mass Assembly (GAMA) 9^h field and over the redshift range 0.039< z <0.134. HI data was collected with the Parkes radio telescope in New South Wales, Australia. Galaxy positions and spectroscopic redshifts are provided by the GAMA survey. By co-adding the spectra of 7049 galaxies extracted from the Parkes data cube, we obtain a strong integrated signal-to-noise ratio of S/N=11.9. The rms noise behaves in a Gaussian manner, with slight deviation caused by the residual radio frequency interference and continuum source emission in the data. We measure average HI properties by integrating stacked spectra over ±300 kms^−1 from rest frame, the range equivalent to the maximum expected width of the HI profile. The resulting average flux density, average HI mass and average HI mass-to-light ratio are, respectively: (S)=(1.07±0.09)mJy, (M_HI)=(2.97±0.38)×10^9h^−2 M_⊙ and (M_HI/L_r)=(1.58±0.39)M_⊙L_⊙^1. We test two different strategies in calculating the cosmic HI mass density (ΩHI). To account for source confusion effect, we apply the confusion factor
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:217:694269
Study programmeTitle: Physics; specializations in: Research
Course: Research
Study programme type: university
Study level: integrated undergraduate and graduate
Academic / professional title: magistar/magistra fizike (magistar/magistra fizike)
Type of resourceText
File originBorn digital
Access conditionsOpen access
Terms of useLicence In copyright icon
Created on2017-04-04 20:03:35