Astronomy's Greatest Hits: The 100 most Cited Papers in Each Year of the First Decade of the 21st Century (2000 - 2009)

Abstract: This paper is based on the 100 most cited papers in astronomy for each year from 2000 to 2009 and from 1995 and 1990. The main findings are: The total number of authors of the top 100 articles per year has more than tripled. This is seen most strongly in papers with more than 6 authors. The yearly number of papers with 5 or fewer authors has declined over the same time period. The most highly cited papers tend to have the largest number of authors and visa versa. The distribution of normalized citation counts versus ranking is constant from year to year except for the top ranked half dozen or so papers. It is closely approximated by a power law. The papers that show the most divergence from the power law all have a high number of citations and are based on large surveys. The average page length of the top 100 papers is one and a half times that for astronomy papers in general. The same 5 journals (A&A, AJ, ApJ, ApJS, and MNRAS) account for 80 to 85% of the total citations for each year of all the journals in the category "Astronomy and Astrophysics" by ISI's Journal Citation Reports. These same 5 journals account for 77% of the 1000 most cited papers. A significant number of articles originally ranked in the top 100 for a year, drop out after 2 to 3 years and are replaced by other articles. Most of the drop-outs deal with extra-galactic astronomy; their replacements deal with non-extra-galactic topics. Indicators of internet access to astronomical web sites such as data archives and journal repositories show increases of between factors of three and ten or more I propose that there are close complementarities between the communication capabilities that internet usage enables and the strong growth in numbers of authors of the most highly cited papers.

• The paper analyzes a decade of data, revealing a more than threefold increase in multi-author studies among the most cited astronomical research.
• It uncovers a significant correlation between paper length and citation counts, indicating that more detailed studies tend to receive higher impact.
• The analysis shows that five key journals consistently account for 80-85% of top citations, highlighting their dominance in the field.

Introduction

The first decade of the 21st century marked a significant transformation in the field of observational astronomy, with not only the implementation of new ground-and space-based observing facilities but also the burgeoning use of digital archives and the internet for research dissemination and collaboration. This paper analyzes the 100 most cited astronomical papers published each year between 2000 and 2009 to investigate the impact these developments have had on the characteristics of scholarly publications and to observe any discernible trends over time.

Trends in Authorship

Observations reveal a remarkable increase in the total number of authors among the set of most-cited papers, with a more than threefold rise over the examined decade. Additionally, the number of unique authors has more than doubled within this time frame, suggesting a sharp growth in collaborative efforts and multidisciplinary involvement within the field. However, this growth is seen most predominantly in papers with a higher number of authors, while publications with fewer authors have seen a decline.

Citation Analysis

An examination of citation counts relative to ranking shows a steady trend, with normalized citation counts displaying a consistent pattern from year to year. Papers ranked 1 through 20 in terms of citations and author count follow a power law distribution, with the most highly cited papers tending to have larger numbers of authors. However, papers with rankings just below the top display significant variability, particularly with a noticeable deviation for a handful of exceptionally highly cited works, many of which are based on results from extensive observational surveys.

Journal Publication Patterns

Throughout the years 2000 to 2008, five journals consistently account for 80 to 85% of total citations from the field of "Astronomy and Astrophysics." These journals (A&A, AJ, ApJ, ApJS, and MNRAS) maintained a dominant presence, although they also represent a comparable majority of astronomy papers published overall. This indicates that while these journals produce most of the highly-cited research, their success rate isn't disproportionate to their publishing volume.

Correlation of Paper Length with Citations

A smaller, but significant, correlation has been found between the length of papers and their citation ranks. On average, the most-cited papers within this prestigious group tend to be longer than the norm for astronomy papers in general, suggesting that detailed, comprehensive research has a higher likelihood of frequent citation.

Implications and Future Research Potential

The surge in authorship and collaborative studies aligns closely with the increase in internet usage for academic purposes, suggesting a relationship between these factors. This paper hints at an evolving research landscape within observational astronomy, with an apparent trend toward large-scale, collaborative, and wide-ranging survey-based projects. Future papers in this series aim to explore further interpretations and explore the scientific content of these exemplary publications, the role of data acquisition, and the significance of data archives in astronomical research.