Characteristics of clockwise and counterclockwise spiral galaxies

Hoehn, C.; Shamir, Lior

doi:10.1002/asna.201311955

Cited by 18 publications

(32 citation statements)

References 16 publications

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“…These results are in agreement with previous studies using manually classified galaxies (Shamir 2016(Shamir , 2012Hoehn & Shamir 2014), but other studies using a smaller number of galaxies (Shamir 2016) or manually classified galaxies (Land et al 2008) do not show statistically significant preference for a certain handedness. The differences between some of the measurements are statistically significant, and were deduced using a fully automatic process, leading to the conclusion that the SDSS photometric pipeline is sen-8 Shamir sitive to the handedness of the galaxy, and provided different photometric measurements for galaxies of different handedness.…”

Section: Discussionsupporting

confidence: 93%

“…Linear regression is applied across the vertical lines of the radial intensity plot for each group of peaks, and the sign of the slopes reflect the direction of the arm, therefore determining the handedness of the galaxy. The algorithm is described in details and numerous examples in (Shamir 2011b;Hoehn & Shamir 2014;Shamir 2012), and the process of galaxy classification is described in (Shamir 2016).…”

Section: Datamentioning

confidence: 99%

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Photometric Asymmetry Between Clockwise and Counterclockwise Spiral Galaxies in SDSS

Shamir

2017

Publ. Astron. Soc. Aust.

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While galaxies with clockwise and counterclockwise handedness are visually different, they are expected to be symmetric in all of their other characteristics. Previous experiments using both manual analysis and machine vision have shown that the handedness of Sloan Digital Sky Survey (SDSS) galaxies can be predicted with accuracy significantly higher than mere chance using its photometric data alone, showing that the photometric pipeline of SDSS is sensitive to the handedness of the galaxy. However, some of these previous experiments were based on manually classified galaxies, and the results may therefore be subjected to bias originated from the human perception. This paper describes an experiment based on a set of 162,514 celestial objects classified as clockwise and counterclockwise spiral galaxies in a fully automatic process, showing that the source of the asymmetry in SDSS database is not the human perception bias. The results are compared to two smaller datasets, and confirm the observation that the handedness of galaxies in SDSS database can be predicted by the way SDSS measures their photometry, and show that the position angle of counterclockwise galaxies computed by SDSS photometry pipeline is consistently higher than the position angle computed for galaxies with clockwise patterns. The experiment also shows statistically significant differences in the measured magnitude of SDSS galaxies, according which galaxies with clockwise patterns imaged by SDSS are brighter than galaxies with counterclockwise patterns. The magnitude of that difference changes across RA ranges, and exhibits a strong correlation with the cosine of the right ascension.

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Section: Discussionsupporting

confidence: 93%

Section: Datamentioning

confidence: 99%

Photometric Asymmetry Between Clockwise and Counterclockwise Spiral Galaxies in SDSS

Shamir

2017

Publ. Astron. Soc. Aust.

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“…One of the most provocative observations that have been noted using these databases is the suspected large‐scale patterns of galaxy rotation direction. Previous experiments showed nonrandom patterns of the distribution of clockwise and counterclockwise galaxies (Hoehn & Shamir 2014; Lee et al 2019a; Lee et al 2019b; Longo 2011; Shamir 2012, 2013, 2016, 2017a, 2017b, 2017c).…”

Section: Introductionmentioning

confidence: 92%

Large‐scale asymmetry between clockwise and counterclockwise galaxies revisited

Shamir

2020

Astron Nachr

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The ability of digital sky surveys to collect and store very large amounts of data provides completely new ways to study the local universe. Perhaps one of the most provocative observations reported with such tools is the asymmetry between galaxies with clockwise and counterclockwise spin patterns. Here I use ∼ 1.7 · 10 5 spiral galaxies from SDSS and sort them by their spin patterns (clockwise or counterclockwise) to identify and profile a possible largescale pattern of the distribution of galaxy spin patterns as observed from Earth. The analysis shows asymmetry between the number of clockwise and counterclockwise spiral galaxies imaged by SDSS, and a dipole axis. These findings largely agree with previous reports using smaller datasets. The probability of the differences between the number of galaxies to occur by chance is (P < 4 · 10 −9 ), and the probability of an asymmetry axis to occur by mere chance is (P < 1.4 · 10 −5 ).

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“…Before the implementation of the program none of the undergraduate students submitted papers to peer-reviewed journals or conferences. After the first year of the program two papers were published [47,42], three papers in 2013 [36,13,39], seven in 2014 [14,43,17,11,26,46,21], six in 2015 [8,24,35,22,15,27], and seven in 2016 [23,38,41,45,40,50,10].…”

Section: Resultsmentioning

confidence: 99%

“…Since different students have different topics of interest, supporting the interest of the students requires a broad range of research topics on which the students can perform their studies, and new topics and disciplines are added every year based on the student request. The first interdisciplinary program was bioinformatics and medical informatics [36,26,24,41], and based on the request of students was enhanced with astroinformatics [17,11,21,35,22,23]. Other programs that followed were Zoology [47,43], art [42], music [14,15,13], literature [39], sports [46,45,50], and human aspects of computing [8,38].…”

Section: Resultsmentioning

confidence: 99%

Authentic computer science undergraduate research experience through computational science and research ownership

Shamir¹

2017

JOCSE

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Research experience has been identified as a high-impact intervention for increasing student engagement and retention in STEM. However, authentic undergraduate research leading to primary authorship peer-reviewed publications is a challenge due to the relatively short time the students work on their capstone projects, and the insufficient preparation of the students as researchers. The challenge is further magnified in the field of computer science, where the absence of "traditional" labs limits the opportunities of undergraduate students to participate in research. Here we present a novel approach to authentic computer science undergraduate research, based on interdisciplinary computational science and student ownership of their research projects. Instead of the traditional role of undergraduate research assistant, the students select their own research topic based on their personal interests, and with the assistance of a faculty complete all stages of their research project. The uniqueness of the approach is its ability to lead to scientific discoveries and peer-reviewed publications such that the primary author is the student, while allowing the student to experience the entire research process, from defining the research question through analysis of the experimental results. In three years the model led to a dramatic increase in the number of undergraduate students who publish primary-author peer-reviewed scientific papers. The intervention increased the number of peer-reviewed student-authored publications from none to a very high rate of about one third of the students, in many cases publishing in the top outlets in their field.

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Characteristics of clockwise and counterclockwise spiral galaxies

Cited by 18 publications

References 16 publications

Photometric Asymmetry Between Clockwise and Counterclockwise Spiral Galaxies in SDSS

Photometric Asymmetry Between Clockwise and Counterclockwise Spiral Galaxies in SDSS

Large‐scale asymmetry between clockwise and counterclockwise galaxies revisited

Authentic computer science undergraduate research experience through computational science and research ownership

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