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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"

32815 results found.

  1. GRB 990217, radio observations
  2. Optical Observations of GRB990217
  3. GRB990123: Caltech STIS Photometry and Images
  4. GRB990123 observations
  5. GRB990123, Optical Observation
  6. GRB 990123: Discovery of the Probable Host Galaxy
  7. GRB 990123: Reduced HST Images
  8. For Immediate Posting to GCN - HST Data GRB 990123 Available
  9. GRB19990123 observations
  10. GRB 990123: BVRI standards in the field
  11. GRB 990123: Updated Keck Spectroscopy Results
  12. GRB981220, field photometry
  13. GRB 990123 NOT Spectrum Update
  14. GRB990123, Optical observation
  15. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  16. GRB 990123: Publicly available reduced HST images
  17. GRB990123, Upcoming HST Service Observations
  18. GRB 990123: New Constraints on Possible Foreground Galaxies
  19. GRB990123 Optical Observations
  20. GRB990123, Probability of gravitational lensing
  21. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  22. GRB 990123: Continued Radio Observations
  23. GRB990123, Preliminary Lens Search Results
  24. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  25. On the Lensing Interpretation of GRB 990123
  26. Search for Potential Images of GRB 990123
  27. Search for Potential Images of GRB 990123
  28. GRB990123, Optical BVRI Observations
  29. GRB 990123: near-infrared observations.
  30. GRB990123, OSSE observations
  31. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  32. "GRB 990123: New BV Observations"
  33. GRB 990123 Optical Follow-Up
  34. GRB 990123; Addendum to GCN 223
  35. GRB 990123: BATSE Observations
  36. GRB 990123 Keck Spectrum update
  37. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  38. GRB990123 Optical Observations
  39. GRB 990123 Spectroscopic Redshifts
  40. GRB 990123: New Optical Observations, Decay Measure
  41. GRB 990123 Optical Follow-Up
  42. GRB 990123: Possible Gravitationally Lensed Burst?
  43. GRB 990123 optical observations
  44. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  45. GRB 990123 radio observations
  46. GRB 990123, new radio source
  47. GRB990123, Optical observation
  48. GRB 990123: Optical Decay Slope
  49. GRB 990123 r-band photometry
  50. GRB 990123 Optical Follow-up
  51. GRB990123, early optical counterpart detection
  52. GRB990123 Optical Observation
  53. GRB 990123: Bright New Source, Possible Optical Transient
  54. GRB 990123, Radio observations
  55. SN 1999E & GRB 980919
  56. Possible identification of SN1999E with GRB980910
  57. Optical Observations of GRB 981220
  58. GRB 981226: radio variable
  59. GRB981220
  60. GRB981220, Optical Observations
  61. GRB 981220 Optical observations
  62. GRB 981226 Optical Observations
  63. GRB 980613: Spectroscopy of the host galaxy
  64. GRB981226, sub-millimeter observations
  65. GRB981220, sub-millimeter observations
  66. GRB 981220 and GRB 981226, optical observations
  67. GRB 981226 radio observations
  68. GRB 981226
  69. GRB 981226 optical observations
  70. radio observations of GRB 981226
  71. GRB981220 B, R and I band observations
  72. GRB 981220:Optical Observations
  73. GRB 981220 optical R and I observations
  74. GRB981226, BeppoSAX Christmas GRB
  75. GRB 981226 - Infrared Observations
  76. GRB 981226 optical observations
  77. GRB 981220
  78. GRB 981220, radio observations
  79. GRB981226 Optical Observation
  80. GRB 981220, radio observations
  81. GRB 981220: BeppoSAX/GRBM results
  82. GRB981220 I-band Observations
  83. GRB 981220
  84. GRB 981220 Optical Observations
  85. GRB 981220, optical observations
  86. GRB 980326/Host Galaxy
  87. GRB981220 IPN error box
  88. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  89. GRB980329 R,I flux calibration and R,I,K upper limits
  90. GRB980425: X-ray revised positions
  91. GRB 980923 BATSE Observations
  92. GRB980703 Very Long Baseline Interferometry
  93. GRB970508 optical observations
  94. GRB971214, association with a Galactic star?
  95. Optical Observations of the Host Galaxy of GRB 980519
  96. GRB980519, Optical Observations
  97. GRB980703, Host galaxy multicolor photometry
  98. GRB980703 - BeppoSAX/GRBM detection
  99. GRB 980703 (NFI observations)
  100. GRB980703 optical photometry

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