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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"

2623 results found.

  1. Possible GRB 040903 detected with INTEGRAL
  2. GRB 040827: Possible detection of optical afterglow
  3. MASTER: GRB040827 possible OT
  4. GRB040825A: optical observations
  5. GRB040825B: optical observations
  6. GRB040825B: Correction to GCN 2657
  7. XRF040812: possible afterglow second Chandra observation
  8. XRF040812: possible afterglow
  9. GRB040624: optical monitoring at TNG
  10. XRF 040701 - optical observations of the decaying Chandra source
  11. GRB040706:observation at University of Miyazaki
  12. GRB 040511: NIR observations with REM
  13. GRB 040423 (=H3175): A Long GRB Localized by HETE
  14. GRB 031203, possible supernova
  15. IPN triangulation of GRB040228 (H3066, H3067)
  16. GRB 031220: Optical observations of Chandra X-ray sources
  17. GRB040106: optical observations with REM+ROSS
  18. IPN triangulation of GRB031219 (large error box)
  19. GRB 031203: Magellan spectrum of possible GRB host
  20. GRB 031203: IR NTTobservations do not confirm REM detection
  21. GRB 031203: IR REM Observations
  22. IPN triangulation of GRB031107 (two large error boxes)
  23. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  24. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  25. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  26. XRF 030824: additional observations at CFHT
  27. IPN detection of continued activity from SGR1806-20
  28. XRF 030824: observations at CFHT
  29. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  30. GRB030922 triangulation (annulus)
  31. GRB030913: OT's limit by MASTER
  32. GRB 030913, optical candidate
  33. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  34. GRB030913 (=H2849): TAROT Observations
  35. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  36. IPN triangulation of GRB030908 (annulus)
  37. IPN detection of continued activity from SGR1806-20
  38. SGR 1808-20 (=H2802): A Possible new SGR
  39. XRF030723: Re-analysis of ROTSE-III early images
  40. GRB030725, possible optical transient
  41. RXTE PCA Observations of SGR1806-20 Region
  42. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  43. MASTER: optical observation GRB030601
  44. GRB 030329: Correction to GCN 2254
  45. GRB 030329: Optical Observations
  46. GRB 030329/SN 2003dh: Possible increase in brightness
  47. GRB 021004: HST observations
  48. IPN triangulation of GRB030518B (annulus)
  49. GRB030429: RTT150 optical observations, a possible host galaxy
  50. GRB 030501: TAROT possible candidate counterpart
  51. GRB030429, possible optical counterpart
  52. SNeIa AS THE POSSIBLE PROGENITORS OF SHORT-DURATION GRBs.
  53. Optical Observations of GRB 030418 with Magellan
  54. IPN triangulation of GRB030422C (annulus)
  55. GRB 030329: SARA Optical Observations
  56. OT GRB 030329: early spectrum
  57. IPN triangulation of GRB030410 (annulus)
  58. GRB 030329, color evolution
  59. GRB030329: Optical observcations
  60. GRB 030329: possible color change
  61. OT GRB light curves and SN predictions
  62. GRB 030329: fitting parameters and re-brightening
  63. GRB 030329: optical observations
  64. 030331 NOT A GRB
  65. GRB030329: ROTSE network observes steepening of decay curve
  66. GRB 030329: optical observations
  67. GRB 030329 follow-up
  68. Possible GRB030323 localized by INTEGRAL
  69. IPN triangulation of GRB030325 (final analysis)
  70. IPN triangulation of GRB030325 (two small error boxes)
  71. GRB030323, ROTSE-III detection of possible optical counterpart
  72. GRB030324, BVRcIc field photometry
  73. GRB030323, possible optical counterpart
  74. GRB030323, BVRcIc field calibration
  75. Possible GRB 030320 localized by INTEGRAL
  76. IPN triangulation of GRB030306 (two small error boxes)
  77. GRB 030226: Ic Observations
  78. GRB 030227 optical afterglow
  79. 030302: NOT A GRB
  80. 030228: NOT A GRB
  81. GRB 030227, possible optical counterpart of XMM-Newton source
  82. GRB030227 - faint tentative OT candidate
  83. Possible break in the GRB 030226 light curve
  84. GRB 030217: Optical Observations at 4, 5, and 6 Days
  85. IPN triangulation of GRB030206 (annulus)
  86. GRB030131: Candidate Optical Afterglow
  87. IPN triangulation of GRB030117 (two large error boxes)
  88. Publicizing GRB Discoveries - A Message from NASA HQ
  89. GRB 030115 : Possible IR counterpart
  90. GRB030115: TAROT optical observations
  91. Possible GRB030113 seen by SPI ACS
  92. Probable GRB030112B seen by SPI ACS
  93. Possible GRB030111 seen by SPI ACS
  94. Possible GRB030110b seen by SPI ACS
  95. Possible GRB 030110 seen by SPI ACS
  96. Possible GRB 20030109 seen by SPI ACS
  97. Possible GRB20030107 seen by SPI-ACS
  98. Possible GRB 20030105 seen by SPI ACS
  99. IPN triangulation of GRB030101 (two large error boxes)
  100. GRB 021211, optical observations

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