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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"

41686 results found.

  1. Chandra detection of the X-ray afterglow of GRB 030226
  2. GRB 030226, further optical/NIR imaging
  3. GRB030227, optical observations
  4. GRB 030226: Ic Observations
  5. GRB030227: Kiso optical upper limit
  6. GRB030227, BVRcIc field photometry
  7. GRB030226, BVRcIc field calibration
  8. GRB 030227 optical afterglow
  9. GRB 030228, optical observations
  10. GRB 030226: Steep Decline
  11. GRB 030227: Confirmed Optical Afterglow (S1-A)
  12. GRB 030226: R band polarimetric observations
  13. GRB 030226: Optical observations
  14. GRB 030227: fading of candidate optical afterglow 'S1-A'
  15. GRB030227:Optical observations
  16. GRB 20030226: Upper limits from recent and historical observations
  17. GRB 030227, possible optical counterpart of XMM-Newton source
  18. GRB030227 - faint tentative OT candidate
  19. GRB 030226, optical observations
  20. XMM-Newton observation of GRB030227
  21. GRB030227: Kiso optical observations
  22. GRB 030227: Kyoto optical observation
  23. GRB 030226, optical light curve
  24. GRB 030226 spectroscopy
  25. GRB030227: refined INTEGRAL position
  26. GRB030227 localized by INTEGRAL
  27. Possible break in the GRB 030226 light curve
  28. GRB 030226 : Predicted light curve
  29. GRB030226: optical observation
  30. GRB 030226: Confirmed decay index
  31. GRB030226: ESI spectroscopy
  32. GRB 030226 simultaneous optical observations
  33. Two absorption systems in GRB 030226
  34. GRB 030226, optical observations
  35. GRB030226: optical observations and refined redshift
  36. GRB030226: Optical decay index
  37. GRB 030226 Optical Spectra and R,I,z' Imaging
  38. GRB 030226, optical observations
  39. GRB 030226: Optical afterglow
  40. GRB030226: Candidate optical afterglow
  41. GRB 030217: Optical Observations at 4, 5, and 6 Days
  42. GRB030217: optical observations
  43. IPN triangulation of GRB030217 (small error box)
  44. IPN triangulation of GRB030215A and GRB030215B (annuli)
  45. GRB030115, WSRT radio observations - correction to GCN 1864
  46. GRB 030131: marginal optical detection
  47. GRB030115, WSRT radio observations
  48. IPN triangulation of GRB030206 (annulus)
  49. GRB 030204: Optical Observations
  50. GRB030204 field photometry
  51. GRB020819: Kiso R and I band observations
  52. GRB030131: Candidate Optical Afterglow
  53. GRB 030115: Optical Observations
  54. GRB 030204, optical observations
  55. IPN triangulation of GRB030202 (annulus)
  56. GRB 030131, optical observations
  57. GRB030131: Kiso optical limit for corrected position
  58. GRB030131: Optical limits for corrected position
  59. GRB 030131: afterglow candidate
  60. GRB 030115, late-time optical observations
  61. GRB030131: corrected INTEGRAL position
  62. Type Ic SN2003L (SN/GRB?), optical spectrum
  63. GRB030131: Kiso Observations
  64. GRB 020819: Host galaxy at Radio Position
  65. IPN triangulation of GRB030131 - CORRECTION
  66. GRB 020819: afterglow candidate
  67. IPN triangulation of GRB030131
  68. GRB030131: Optical limit
  69. GRB 030131 optical observations
  70. GRB030131: refined position
  71. GRB 030131 optical observations
  72. A long GRB detected by INTEGRAL
  73. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  74. Type Ic SN2003L (SN/GRB?) Radio Observations
  75. GRB030115 submm upper limit
  76. GRB 030115: Further IR observations with IRSF/SIRIUS
  77. GRB 030115: Radio detection of IR candidate
  78. GRB 030115, simultaneous observations by BOOTES-1
  79. GRB 030115: IR observations with IRSF/SIRIUS
  80. GRB030115: R-band counterpart of IR candidate
  81. GRB030115, afterglow candidate
  82. GRB 021211: R-band observations at late-time
  83. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  84. IPN triangulation of GRB030115B (small error box)
  85. GRB 030115 : Possible IR counterpart
  86. GRB 030115: Radio Observations
  87. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  88. Distribution of INTEGRAL SPI-ACS triggers
  89. GRB030115: R-band observations at Asiago
  90. GRB030115: TAROT optical observations
  91. GRB 021211: VLT spectrum
  92. GRB 030115: APO Optical Observations
  93. GRB 030115, no optical candidate
  94. GRB 030115, optical observations
  95. GRB 030115, optical candidate
  96. Information about where HETE will be pointing
  97. IPN triangulation of GRB030109 (annulus)
  98. IPN triangulation of GRB030105 (large error box)
  99. Coronas-F -Wind triangulation of GRB030102
  100. VLT spectroscopy of the probable host of GRB 021211

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