Skip to main content
New! BOOM Notices and Schema v7.0.0. See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

35254 results found.

  1. GRB 990510 optical observations
  2. IPN localization of GRB990510
  3. GRB 990506 Radio Observations
  4. GRB 990123, optical monitoring
  5. GRB 990506: BATSE Observations
  6. GRB 990506, optical observations
  7. GRB 990510: Final BeppoSAX-WFC Coordinates
  8. GRB 990506, Optical Observations
  9. GRB 990506 optical observations
  10. GRB 990506 optical observations
  11. GRB 990506, optical observations
  12. GRB990506 observation plan
  13. Refined IPN error box for GRB990506
  14. GRB 990506: Limits on the possible optical transient
  15. GRB 990506, armchair astronomy
  16. GRB 990506, optical observations from +1 to +3 hours
  17. GRB 990506, optical observations
  18. GRB990506 observation plan
  19. New IPN/RXTE error box for GRB990506
  20. IPN localization for GRB990506
  21. GRB 970228: Redshift and properties of the host galaxy
  22. IPN localization of GRB990427
  23. GRB981220 VLBA observations
  24. GRB990321 REFINED IPN ANNULUS
  25. GRB990323 PRECISE IPN POSITION
  26. GRB990321 IPN TRIANGULATION
  27. GRB 990316 Optical Observations
  28. GRB 990316, Radio observations
  29. GRB 990316, Optical observations
  30. GRB990316, Optical observations
  31. GRB 990316 optical observations
  32. GRB990316: simultaneous optical observation
  33. ASM/IPN error box for GRB 990308 (BATSE #7457)
  34. GRB990308 not a new SGR
  35. GRB 990308a and GRB 990308b
  36. GRB990308 (Trig. 7457), optical observations
  37. GRB981220, IPN localization
  38. GRB 981220, radio observations
  39. GRB 990123, Field Photometry
  40. GRB 990217 Optical Observations
  41. GRB 990217, radio observations
  42. Optical Observations of GRB990217
  43. GRB990123: Caltech STIS Photometry and Images
  44. GRB990123 observations
  45. GRB990123, Optical Observation
  46. GRB 990123: Discovery of the Probable Host Galaxy
  47. GRB 990123: Reduced HST Images
  48. For Immediate Posting to GCN - HST Data GRB 990123 Available
  49. GRB19990123 observations
  50. GRB 990123: BVRI standards in the field
  51. GRB 990123: Updated Keck Spectroscopy Results
  52. GRB981220, field photometry
  53. GRB 990123 NOT Spectrum Update
  54. GRB990123, Optical observation
  55. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  56. GRB 990123: Publicly available reduced HST images
  57. GRB990123, Upcoming HST Service Observations
  58. GRB 990123: New Constraints on Possible Foreground Galaxies
  59. GRB990123 Optical Observations
  60. GRB990123, Probability of gravitational lensing
  61. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  62. GRB 990123: Continued Radio Observations
  63. GRB990123, Preliminary Lens Search Results
  64. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  65. On the Lensing Interpretation of GRB 990123
  66. Search for Potential Images of GRB 990123
  67. Search for Potential Images of GRB 990123
  68. GRB990123, Optical BVRI Observations
  69. GRB 990123: near-infrared observations.
  70. GRB990123, OSSE observations
  71. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  72. "GRB 990123: New BV Observations"
  73. GRB 990123 Optical Follow-Up
  74. GRB 990123; Addendum to GCN 223
  75. GRB 990123: BATSE Observations
  76. GRB 990123 Keck Spectrum update
  77. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  78. GRB990123 Optical Observations
  79. GRB 990123 Spectroscopic Redshifts
  80. GRB 990123: New Optical Observations, Decay Measure
  81. GRB 990123 Optical Follow-Up
  82. GRB 990123: Possible Gravitationally Lensed Burst?
  83. GRB 990123 optical observations
  84. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  85. GRB 990123 radio observations
  86. GRB 990123, new radio source
  87. GRB990123, Optical observation
  88. GRB 990123: Optical Decay Slope
  89. GRB 990123 r-band photometry
  90. GRB 990123 Optical Follow-up
  91. GRB990123, early optical counterpart detection
  92. GRB990123 Optical Observation
  93. GRB 990123: Bright New Source, Possible Optical Transient
  94. GRB 990123, Radio observations
  95. SN 1999E & GRB 980919
  96. Possible identification of SN1999E with GRB980910
  97. Optical Observations of GRB 981220
  98. GRB 981226: radio variable
  99. GRB981220
  100. GRB981220, Optical Observations

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov