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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"

42583 results found.

  1. GRB990506 Optical observations
  2. GRB990506 observation plan
  3. New IPN/RXTE error box for GRB990506
  4. IPN localization for GRB990506
  5. GRB 970228: Redshift and properties of the host galaxy
  6. GRB981220 VLBA observations
  7. GRB980425 Optical observations of exponential decline at late time
  8. GRB990323 PRECISE IPN POSITION
  9. GRB990321 IPN TRIANGULATION
  10. GRB 990316 Optical Observations
  11. GRB 990316, Radio observations
  12. GRB 990316, Optical observations
  13. GRB990316, Optical observations
  14. GRB 990316 optical observations
  15. GRB990316: simultaneous optical observation
  16. GRB990316 - Optical null results
  17. ASM/IPN error box for GRB 990308 (BATSE #7457)
  18. GRB990308 not a new SGR
  19. GRB 990308a and GRB 990308b
  20. GRB990308 (Trig. 7457), optical observations
  21. GRB990308, Possible new SGR~0209+70
  22. GRB981220, IPN localization
  23. GRB 981220, radio observations
  24. GRB 990123, Field Photometry
  25. GRB 990217, radio observations
  26. BATSE Resumes Normal Operations
  27. BATSE Flight Anomaly
  28. GRB990217: BeppoSAX/GRBM data
  29. Optical Observations of GRB990217
  30. GRB990123: Caltech STIS Photometry and Images
  31. GRB990123 observations
  32. GRB990217, WFC position
  33. GRB990123, Optical Observation
  34. GRB 990123: Discovery of the Probable Host Galaxy
  35. GRB 990123: Reduced HST Images
  36. For Immediate Posting to GCN - HST Data GRB 990123 Available
  37. GRB19990123 observations
  38. GRB 990123: Updated Keck Spectroscopy Results
  39. GRB981220, field photometry
  40. GRB 990123 NOT Spectrum Update
  41. GRB990123, Optical observation
  42. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  43. GRB 990123: Publicly available reduced HST images
  44. GRB990123, Upcoming HST Service Observations
  45. GRB990123, 15-GHz limits
  46. GRB 990123: New Constraints on Possible Foreground Galaxies
  47. GRB990123 Optical Observations
  48. GRB990123, Probability of gravitational lensing
  49. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  50. GRB 990123: Continued Radio Observations
  51. GRB990123, Preliminary Lens Search Results
  52. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  53. On the Lensing Interpretation of GRB 990123
  54. Search for Potential Images of GRB 990123
  55. Search for Potential Images of GRB 990123
  56. GRB990123, Optical BVRI Observations
  57. GRB 990123: near-infrared observations.
  58. GRB990123, OSSE observations
  59. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  60. GRB990123: NIR Observation
  61. GRB990123, ASCA X-ray observation of afterglow
  62. GRB 990123 Optical Follow-Up
  63. GRB 990123: BATSE Observations
  64. GRB 990123 Keck Spectrum update
  65. GRB990123 IPN annulus
  66. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  67. GRB990123 Optical Observations
  68. GRB 990123 Spectroscopic Redshifts
  69. GRB 990123: New Optical Observations, Decay Measure
  70. GRB 990123 Optical Follow-Up
  71. GRB 990123: Possible Gravitationally Lensed Burst?
  72. GRB 990123 optical observations
  73. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  74. GRB 990123 radio observations
  75. GRB 990123, new radio source
  76. GRB990123 optical observations
  77. GRB990123, Optical observation
  78. GRB 990123: Optical Decay Slope
  79. GRB 990123 r-band photometry
  80. GRB 990123 Optical Follow-up
  81. GRB990123, early optical counterpart detection
  82. GRB990123 Optical Observation
  83. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  84. GRB990123, refined SAX-WFC position
  85. GRB 990123: Bright New Source, Possible Optical Transient
  86. GRB 990123, Radio observations
  87. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  88. SN 1999E & GRB 980919
  89. Possible identification of SN1999E with GRB980910
  90. Optical Observations of GRB 981220
  91. GRB 981226: radio variable
  92. GRB981220
  93. GRB981220, Correction to GCN 179
  94. GRB981220, Optical Observations
  95. GRB 981220 Optical observations
  96. GRB 981226 Optical Observations
  97. GRB 980613: Spectroscopy of the host galaxy
  98. GRB981226, sub-millimeter observations
  99. GRB981220, sub-millimeter observations
  100. GRB 981220 and GRB 981226, optical observations

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