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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"

15725 results found.

  1. GRB 030115: Optical Observations
  2. GRB 030204, optical observations
  3. GRB 030131, optical observations
  4. GRB030131: Kiso optical limit for corrected position
  5. GRB030131: Optical limits for corrected position
  6. GRB 030115, late-time optical observations
  7. Type Ic SN2003L (SN/GRB?), optical spectrum
  8. GRB 020819: Host galaxy at Radio Position
  9. GRB 020819: afterglow candidate
  10. GRB030131: Optical limit
  11. GRB 030131 optical observations
  12. GRB 030131 optical observations
  13. Type Ic SN2003L (SN/GRB?) Radio Observations
  14. GRB 030115, simultaneous observations by BOOTES-1
  15. GRB030115: R-band counterpart of IR candidate
  16. GRB 021211: R-band observations at late-time
  17. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  18. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  19. GRB030115: TAROT optical observations
  20. GRB 030115: APO Optical Observations
  21. GRB 030115, no optical candidate
  22. GRB 030115, optical observations
  23. GRB 030115, optical candidate
  24. GRB 021211: Probable Host and Underlying Supernova
  25. GRB021211, radio observations
  26. GRB 021112: Evidence for Another Dark Optical Afterglow
  27. GRB 021219: OSN optical observations
  28. GRB021219, optical observations
  29. GRB021219, optical observation by MASTER
  30. GRB021211: APO optical observations
  31. IPN detection of continued activity from SGR1806-20
  32. XRF 020903 : HST observations
  33. GRB 021201: Optical Observations
  34. GRB 021211, optical observations
  35. GRB 021211: CTIO observations
  36. GRB021211: Measurement of Early Time Afterglow
  37. GRB021211, BVRI field photometry
  38. GRB021211: Optical observations in CrAO
  39. GRB 021211, optical observations
  40. GRB 021211: Optical Observations
  41. GRB021211: Kiso Observations
  42. GRB021204: Kiso Observations
  43. GRB 021201, optical observations
  44. GRB 021211: Radio Observations
  45. GRB021211: Optical observations
  46. GRB 021201 (short/hard), NOT observations
  47. GRB021211 - Upper limits from recent and historical observations
  48. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  49. HETE 2493: Optical observations
  50. HETE 2493: Optical observations
  51. HETE 2493: Optical candidate
  52. GRB 021204: Optical Observations at RIKEN
  53. GRB 021201: Optical Observations
  54. GRB 021201: BOOTES simultaneous optical observations
  55. GRB021004, late time optical observations
  56. IPN detection of continued SGR1900+14 activity
  57. GRB021113, SPI ACS observation
  58. GRB021113: optical observations at Bisei
  59. GRB 021113: Evidence for a Dark Optical Afterglow
  60. GRB 021112: Variable Source in R-band search
  61. GRB021112: Optical Observations
  62. GRB 021113: Optical observations
  63. GRB 021112: RAPTOR Observations
  64. GRB 021113: Optical Observations
  65. GRB 021113: Optical Observations
  66. GRB021113 (=H2449): A Long GRB Localized by HETE
  67. GRB 021112: Optical Observations
  68. GRB021112 (=H2448): A Long GRB Localized by HETE
  69. GRB 021016: Optical Observations
  70. GRB021104: Optical Observations
  71. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  72. GRB021104: Optical observations
  73. GRB021104: optical observations
  74. GRB021104: Candidate present in DSS
  75. GRB021104: possible optical afterglow
  76. GRB021004, late-time optical observations
  77. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  78. GRB 021004: optical observations
  79. GRB021004: Optical Observations
  80. GRB 020813; likely host galaxy.
  81. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  82. GRB 021016, optical observations
  83. GRB 021004: VRI observations at TNG: possible break
  84. GRB021016, optical observations
  85. GRB 021008, optical observations
  86. GRB021016(=H2397): A Long GRB Localized by HETE
  87. GRB021004: Optical Observations
  88. GRB 021004: optical spectroscopy on Oct 11
  89. GRB021004: High-resolution optical spectroscopy
  90. XRF 020903: flattening of the optical light curve.
  91. GRB021004: Optical Observations
  92. GRB021004 Chandra HETG Observations
  93. GRB 021004: Optical/NIR Observations
  94. GRB 021004: Additional V-band Polarimetric Observations
  95. GRB021004: optical observation
  96. GRB 021004: WC wind?
  97. GRB021004: NIR and Optical observations
  98. GRB 021004: Optical measurement at OHP
  99. GRB 021004: Optical observations, AUDE network
  100. GRB 021004 - Unusual Radio-to-Submm Spectrum

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