Scientific impact of large telescopes 1991-8

Below we summarise the results from our analysis of the 1000 top-cited astrophysics papers 1991-8, under the following headings:

1. Impact of individual telescopes (from Benn & Sanchez 2001)
2. Impact of individual countries (from Sanchez & Benn 2004)
3. Impact of individual institutions (not published elsewhere)
4. Impact of individual authors (not published elsewhere)

In Benn & Sanchez (2001, PASP, 113, 385), we presented a detailed analysis of the relative scientific impact of individual ground-based and space telescopes. The WHT had more articles in Nature than any other ground-based optical telescope during this period, and 1995-8 WHT papers in all journals garnered more citations than those from any other ground-based optical telescope apart from Keck and CFHT.

Abstract:
The scientific impacts of telescopes worldwide have been compared on the basis of their contributions to (a) the 1000 most-cited astronomy papers published 1991-8 (125 from each year), and (b) the 452 astronomy papers published in Nature 1989-98. 1-m and 2-m ground-based telescopes account for approximately 5% of the citations to the top-cited papers, 4-m telescopes 10%, Keck I/II 4%, sub-mm and radio telescopes 4%, HST 8%, other space telescopes 23%. The remaining citations are mainly to theoretical and review papers. The strong showing by 1-m and 2-m telescopes in the 1990s augurs well for the continued scientific impact of 4-m telescopes in the era of 8-m telescopes. The impact of individual ground-based optical telescopes is proportional to collecting area (and approximately proportional to capital cost). The impacts of the various 4-m telescopes are similar, with CFHT leading in citation counts, and WHT in Nature papers. HST has about 15 times the citation impact of a 4-m ground-based telescope, but cost > 100 times as much. Citation counts are proportional to counts of papers published in Nature, but for radio telescopes the ratio is a factor ~ 3 smaller than for optical telescopes, highlighting the danger of using either metric alone to compare the impacts of different types of telescope. Breakdowns of citation counts by subject (52% extragalactic), and journal (ApJ 44%, Nature 11%, MNRAS 9%, A&A 6%) are also presented.

Our findings were discussed in a news feature in Nature (2000 Nov 2, p.12).

In Sanchez & Benn (2004, Astr. Nachr., 325, 445), we used the same 1991-8 citations database to measure the relative scientific impact of different countries.
Abstract:
The impact of astronomical research carried out by different countries has been compared by analysing the 1000 most-cited astronomy papers published 1991-8 (125 from each year). 61% of the citations are to papers with first authors at institutions in the USA, 11% in the UK, 5% in Germany, 4% in Canada, 3% in Italy and 3% in France. 17% are to papers with first authors in ESO countries. The number of citations is approximately proportional to the number of IAU members in a given country. The number of citations per IAU astronomer is highest in the USA, Switzerland and the UK. Within continental Europe, the number of citations per IAU astronomer varies little from country to country, but is slightly higher in the north than in the south. The sample of 1000 papers maps regional subject preferences. 62% of the extragalactic papers in the sample were published from the USA, 15% from the UK, 23% from other countries (mainly in continental Europe). 62% of the papers on stars were also published from the USA, but the fractions from the UK and from other countries are 2% and 36% respectively.

The 30 most-productive institutions are ranked below by 1991-8 citation impact. These results are not published elsewhere.

Institution   Country          Papers               Citations
                           91-4 95-8 91-8    1991-4  1995-8  1991-8

Harvard       USA           25   25   50       5.2     4.9     5.1 
GSFC          USA           20   33   53       4.1     6.0     5.1 
Princeton     USA           28   20   48       4.9     3.8     4.3 
Caltech       USA           13   24   37       2.3     5.7     4.0 
IOACambridge  UK            22   12   34       4.6     2.7     3.6 
STScI         USA           16   16   32       2.6     4.0     3.3 
Berkeley      USA           13   12   25       3.7     2.1     2.9 
Hawaii        USA           12   15   27       2.5     2.8     2.7 
Arizona       USA           13   14   27       2.3     3.0     2.7 
Durham        UK             4   13   17       0.8     3.2     2.0 
UCSC          USA           13    6   19       2.2     1.6     1.9 
MPIE          Germany       11    8   19       2.0     1.5     1.8 
Geneva        Switzerland   10    2   12       2.7     0.7     1.7 
LLNL          USA            5    6   11       1.7     1.7     1.7 
Carnegie      USA           10   10   20       1.8     1.6     1.7 
Toronto       Canada         7    9   16       1.2     2.0     1.6 
MIT           USA            9    6   15       1.4     1.0     1.2 
JHU           USA            4   10   14       0.6     1.8     1.2 
MPIA          Germany        4   10   14       0.5     1.7     1.1 
Tokyo         Japan          3    7   10       0.8     1.2     1.0 
Amsterdam     Netherlands    2    9   11       0.3     1.7     1.0 
Oxford        UK             9    0    9       2.0     0.0     1.0 
NRAO          USA            5    3    8       1.0     0.9     1.0 
Mt. Stromlo   Australia      5    5   10       1.3     0.8     1.0 
Yvette        France         4    5    9       0.9     0.8     0.8 
UCSD          USA            3    4    7       0.6     1.0     0.8 
Leicester     UK             6    1    7       1.5     0.2     0.8 
Wisc./Madison USA            5    2    7       1.0     0.3     0.7 
UCSB          USA            4    1    5       1.3     0.2     0.7 
MPIH          Germany        5    3    8       0.9     0.4     0.7 

Note that only the institution of the first author has been considered. The top 5 are large institutions: Harvard, GSFC (both institutions publishing a mixture of solar-system, stellar and extragalactic work), Princeton (hot stars, extragalactic), Caltech (mostly extragalactic) and IOA Cambridge (all extragalactic), with no significant change in productivity between 1991 and 1998.

Abt (1993, PASP, 105, 437), using a count of published papers, found the top 4 US institutions to be Harvard, GSFC, Caltech and STScI. The top 4 non-US institutions after IOA Cambridge are the University of Durham, the Max Planck Institute for Extraterrestrial Physics in Garching, Geneva Observatory and the University of Toronto. The Durham and Toronto papers are all on extragalactic topics, most of those from MPIE and Geneva are on stars.

LLNL = Lawrence Livermore, USA; MPIA = Max Planck Inst. Astrophysics, Munich; MPIE = Max Planck Inst. Extraterrestrial Physics, Garching; MPIH = Max Planck Inst. Astronomy, Heidelberg.

These results are not published elsewhere.

The ISI citations database gives the surname and initials of the first author of each paper. The 1000 top papers 1991-8 include 732 different names for first author. The most frequent are C. Alcock (5), J.N. Bahcall (6), R.C. Kennicutt (6), R. Narayan (9) and S.E. Woosley (6), all publishing from the USA. Of the 16 authors with 4 or more entries, 13 publish mainly from the USA, 1 from USA/NL, 1 from Canada, and 1 from UK/Germany. Their papers are on a variety of high-profile topics, e.g. microlensing, gamma-ray bursts, advection-dominated accretion, dark matter, measurement of the Hubble constant. Seven of the 60 authors (12%) with 3 or more papers in the top 1000 are UK-based. Below are listed first authors with 3 or more papers amongst the top-cited 1000 from 1991-8.

Papers Author

   9   NARAYAN R              

   6   BAHCALL JN             
   6   KENNICUTT RC           
   6   WOOSLEY SE             

   5   ALCOCK C               

   4   BARNES JE              
   4   COWIE LL               
   4   KAUFFMANN G            
   4   LANZETTA KM            
   4   LILLY SJ               
   4   MADAU P                
   4   MUSHOTZKY RF           
   4   NAVARRO JF             
   4   STEIDEL CC             
   4   VANDERMAREL RP         
   4   WHITE SDM              

   3   BAHCALL NA             
   3   BAUGH CM               
   3   BENNETT CL             
   3   BURROWS A              
   3   CARLBERG RG            
   3   CEN RY                 
   3   CHABOYER B             
   3   CONDON JJ              
   3   EDGE AC                
   3   ELLIS RS               
   3   EVRARD AE              
   3   FABIAN AC              
   3   FISHER KB              
   3   FUKUGITA M             
   3   GORSKI KM              
   3   HAARDT F               
   3   HASINGER G             
   3   HENRY JP               
   3   HILLENBRAND LA         
   3   HOLTZMAN JA            
   3   IGLESIAS CA            
   3   KATZ N                 
   3   KOUVELIOTOU C          
   3   MAEDER A               
   3   MCWILLIAM A            
   3   MIRABEL IF             
   3   MOORE B                
   3   MULCHAEY JS            
   3   NANDRA K               
   3   PACZYNSKI B            
   3   PEACOCK JA             
   3   PETTINI M              
   3   RIESS AG               
   3   SAHA A                 
   3   SANDAGE A              
   3   SCOVILLE NZ            
   3   SONGAILA A             
   3   STONE JM               
   3   TANAKA Y               
   3   THOMPSON DJ            
   3   WAXMAN E               
   3   WORTHEY G              
   3   WRIGHT EL              

According to Schulman et al (1997, PASP, 109, 1278), the fraction of single-author papers in the astronomical literature declined from 40% in 1975 to 14% in 1995. In the ISI database, the fraction of papers with one author declined from 13 to 8% over 1991 to 1998, that with 1-4 authors from 71 to 54%, that with 5-8 authors is approximately constant, and that with > 8 authors has risen from 13 to 26%. There is no correlation between number of authors and citation ranking of paper. The paper with the largest number of authors (103) is by Korista et al (1995). The median number of authors for papers using data from 4-m class or smaller ground-based telescopes is 4. The median for Keck and HST is 6. Most of the papers with more than 10 authors are based on data from space telescopes.