Bibliography Statistics - Definitions and Conventions

DEFINITIONS

Only papers already published in refereed journals that present specific data from Chandra observations (Category 1 below) are included in these plots, except for plots by publication year, which include refereed papers in Categories 1 and 2 (if flag A, B, or C is set). These latter are what we define throughout as Chandra Science Papers.

Definition of Tabulated Bibliographic Categories

1. Presents specific Chandra observations
2. Refers to published Chandra results
3. Predicts Chandra results (could be either astrophysical theory or data extrapolation)
4. Describes instrumentation, software or operations
5. Cannot be classified

and any of these FLAGS may accompany the above categories:

1. Complementary observations
2. Simulations or Follow-up Analysis
3. Astrophysical Theory that explains Chandra results
4. Instrument flags (ACIS, HRC, HETG, LETG, HRMA, PCAD, EPHIN)
5. Operations

Definition of Tabulated Programs

The number of programs (approved proposals) tallied in tables or plots includes only those programs for which all approved observations have been completed.

Plot Naming Conventions

• by:   x-axis of plot
  example: Papers by program type


• with:   types of plotted points or bars
  (e.g., different cycles, different science or proposal categories)
  example: Papers by program type with cycles


• per:   normalization of each bin value
  example: Papers per ksec by cycle


• for:   plots separated
  (e.g., one plot for each cycle)
  example: Papers per ksec by program type for Cycle1

Different Science Categories

When we plot with (separate bars for) different science categories, we want to avoid too many bars, so we've reduced Science Categories from 11 in the RPS and our Database to the 8 below.

• Solar System
• Stars and WD
• WD Binaries and CV BH and NS Binaries
• SN, SNR and Isolated NS
• Normal Galaxies: Diffuse Emission Normal Galaxies: X-ray Populations
• Active Galaxies and Quasars
• Clusters of Galaxies
• Extragalactic Diffuse Emission and Surveys Galactic Diffuse Emission and Surveys

Different Program Types - VLP, LP, GO, GTO, TOO, DDT

Large Project (LP) programs were first initiated in Cycle 3. Very Large Project (VLP) programs were only begun in Cycle 5. Therefore, comparisons of V/LP programs to normal GO programs by program type can only be made for very recent Cycles, for which statistics are still poor. Plots arrayed by ksec may thus be more informative.

Time Bins Used in Plots

We are using geometrically spaced bins of exposure times (widths of 10, 20, 40, 80,... ksec), until we get into the V/LP range. So use ksec bin edges 0, 10, 30, 70, 150, 300, 1000, i.e.,

• t <= 10
• 10 < t <= 30
• 30 < t <= 70
• 70 < t <= 150
• 150 < t <= 300
• 300 < t <= 1000

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.    Email: cxcweb@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2004. All rights reserved.

Last modified: 05/15/06