Using an assumption about the monotony of spiral arms to determine the orientation angles of galaxies

Fridman, A. M.; Poltorak, S. G.

doi:10.1111/j.1365-2966.2010.16229.x

Cited by 5 publications

(2 citation statements)

References 13 publications

(19 reference statements)

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“…In this work we have used the MSA method (Poltorak & Fridman 2007, Fridman & Poltorak 2010. This method allows us to obtain values of both inclination and position angle.…”

Section: Inclinationmentioning

confidence: 99%

Pitch angle variations in spiral galaxies

Савченко¹,

Решетников²

2013

Monthly Notices of the Royal Astronomical Society

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We present a detailed photometric study and measurements of spiral arm pitch angles for a sample of 50 non-barred or weakly barred grand-design spiral galaxies selected from Sloan Digital Sky Survey. In order to find pitch angles, we used a new method based on the window Fourier analysis of their images. This method allows us not only to infer the average pitch angle, but to obtain its value as a function of galactocentric radius as well. Our main results are as follows:(1) Spiral arms of most galaxies cannot be described by a single value of the pitch angle. About 2/3 of galaxies demonstrate pitch angle variations exceeding 20%. In most galaxies in the sample their pitch angle decreases by increasing the distance from the centre.(2) Pitch angle variations correlate with the properties of galaxies -with the shape of the surface brightness distribution (envelope-type or truncated disc), and with the sign of stellar disc colour gradient.(3) More luminous and bright bulges produce more tightly wound spiral arms, that is in agreement with current models for spiral arms formation.

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“…In this work we have used the MSA method (Poltorak & Fridman 2007, Fridman & Poltorak 2010. This method allows us to obtain values of both inclination and position angle.…”

Section: Inclinationmentioning

confidence: 99%

Pitch angle variations in spiral galaxies

Савченко¹,

Решетников²

2013

Monthly Notices of the Royal Astronomical Society

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“…In this paper, we decided to use the relatively new method of spiral-arm monotony (SAM; Poltorak and Fridman 2007;Fridman and Poltorak 2010). This method is based on the assumption that every spiral arm is a monotonic function, i.e., following along the spiral from the galaxy center to the periphery, the radius must increase monotonically ( dr dφ > 0, where r is the distance from a point in the spiral arm to the galaxy center and φ is the azimuthal angle).…”

Section: Determining the Orientation Of Galaxy Disksmentioning

confidence: 99%

Pitch angles of distant spiral galaxies

Савченко

Решетников

2011

Astron. Lett.

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We have studied the pitch angles of spiral arms for 31 distant galaxies at z~0.7 from three Hubble Deep Fields (HDF-N, HDF-S, HUDF). Using the pitch angle - rotation velocity relation calibrated from nearby galaxies, we have estimated the rotation velocities of galaxies from the deep fields. These estimates have a low accuracy (~50 km/s), but they allow low-mass and giant galaxies to be distinguished. The Tully-Fisher relation constructed using our velocity estimates shows satisfactory agreement with the actually observed relations for distant galaxies and provides evidence for the luminosity evolution of spiral galaxies.Comment: 9 pages, 6 figure

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Galaxies decomposition with spiral arms – II. A multiwavelength case study of M 51

Marchuk,

Chugunov,

Gontcharov

et al. 2024

Monthly Notices of the Royal Astronomical Society

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Spiral structure can contribute significantly to a galaxy’s luminosity. However, only rarely are proper photometric models of spiral arms used in decompositions. As we show in the previous work, including the spirals as a separate component in a photometric model of a galaxy would both allow to obtain their structural parameters, and reduce the systematic errors in estimating the parameters of other components. Doing so in different wavebands, one can explore how their properties vary with the wavelength. In this paper, second in this series, we perform decomposition of M 51 in 17 bands, from the far UV to far IR, using imaging from the DustPedia project. We use the same 2D photometric model of spiral structure where each arm is modelled independently. The complex and asymmetric spiral structure in M 51 is reproduced relatively well with our model. We analyze the differences between models with and without spiral arms, and investigate how the fit parameters change with wavelength. In particular, we find that the spiral arms demonstrate the largest width in the optical, whereas their contribution to the galaxy luminosity is most significant in the UV. The disk central intensity drops by a factor of 1.25–3 and its exponential scale changes by 5–10% when spiral arms are included, depending on wavelength. Taking into account the full light distribution across the arms, we do not observe the signs of a long-lived density wave in the spiral pattern of M 51 as a whole.

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Using an assumption about the monotony of spiral arms to determine the orientation angles of galaxies

Cited by 5 publications

References 13 publications

Pitch angle variations in spiral galaxies

Pitch angle variations in spiral galaxies

Pitch angles of distant spiral galaxies

Galaxies decomposition with spiral arms – II. A multiwavelength case study of M 51

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