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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"

908 results found.

  1. GRB 091208B: GAO 150cm telescope Optical Observation
  2. GRB 091208B: MITSuME Akeno Optical Observation
  3. GRB 091208B: MITSuME Okayama Optical Observation
  4. GRB 091127: GAO 150cm telescope Optical Observation
  5. GRB 091020: Early TLS Multicolor detections, red afterglow
  6. GRB091024: VRcIc Afterglow Observations
  7. GRB 090831B: MITSuME optical upper limits
  8. GRB 090807: MITSuME optical upper limit
  9. GRB090618: Spectrum and photometry from 6.0m BTA
  10. GRB 090529: MITSuME optical observation
  11. Strong radio emission from SN 2007bg one year after the explosion - detection of spreading, off-axis GRB jet?
  12. GRB 090529: TLS Afterglow Observations
  13. GRB 090426: GAO 150cm telescope Optical Observation
  14. GRB 090426: Okayama MITSuME optical observation
  15. GRB 090423: Near infrared observation at Okayama Observatory
  16. GRB 080410: GAO 150cm telescope Optical Observation
  17. GRB 080408A: GAO 150cm telescope Optical Observation
  18. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  19. GRB 090417B: MITSuME Okayama optical upper limits
  20. GRB 090410: MITSuME optical upper limits
  21. GRB 090401B: Upper limits of MITSuME optical observation
  22. GRB 090313: MITSuME Okayama observation
  23. GRB 081222: MITSuME optical observation
  24. GRB081203A: Optical observations at Ishigaki
  25. GRB 081025: TLS upper limits
  26. GRB 080905A: MITSuME Akeno optical upper limits
  27. SGR 0501+4516: optical observations
  28. GRB 080810: RTT150 optical observations
  29. GRB 080810: RTT150 optical observations
  30. GRB080810: MITSuME optical observation
  31. GRB 080710: Optical observation with MITSuME Okayama
  32. GRB 080710: TLS observations, steepening afterglow decay
  33. GRB 080702A: MITSuME Akeno optical upper limits
  34. GRB080613B: MITSuME upper limits
  35. GRB080613A: Optical upper limits with Okayama MITSuME telescope
  36. GRB 080605: TLS 3rd Epoch - Source Confusion
  37. GRB080605: optical observation with the MITSuME-OAO telescope
  38. GRB 080605: TLS RRM Afterglow
  39. GRB 080604: MITSuME Okayama observation
  40. GRB 080506: TLS afterglow detection in VRIZ
  41. GRB 080503: MITSuME Ishigakijima optical upper limits
  42. GRB 080503: MITSuME Akeno optical upper limits
  43. GRB 080325: MITSuME Akeno optical upper limits
  44. GRB 080310: GAO 150cm telescope Optical Observation
  45. GRB080310: Optical observation by MITSuME telescope
  46. GRB 080307: GAO 150cm telescope Optical Observation
  47. GRB 080229A: GAO 150cm telescope Optical Observation
  48. GRB080307: Optical upper limits
  49. GRB080229: Possible optical afterglow
  50. GRB080212: Optical afterglow candidate observed by MITSuME Telescope
  51. GRB 080205: GAO 150cm telescope Optical limit
  52. Transient 080109/SN 2008D: Spectroscopic Evolution and Re-Classification
  53. Transient 080109/ SN 2008D, metallicity of the host galaxy
  54. Transient 080109/ SN 2008D, IR Spectrum
  55. XRF 080109 / SN 2008D: spectroscopic evolution
  56. Detailed Spectroscopic ID of SN 2008D (Transient in NGC 2770)
  57. Spectroscopic classification of SN 2008D (Transient in NGC 2770)
  58. GRB071118 MITSuME OAO optical observation
  59. GRB071112C: Errata of MITSuME Ic band photometry
  60. GRB 071112C MITSuME Akeno early optical observation
  61. GRB071112C MITSuME Okayama Optical Observation
  62. GRB 071020: MITSuME Akeno optical observations
  63. GRB071021: MITSuME Okayama Optical Upper Limits
  64. GRB 071011: MITSuME Optical Observations
  65. GRB 071010B correction to GCN 6892 optical observations
  66. GRB 071010B optical photometry
  67. GRB 071010B possible optical transient
  68. GRB 070917: MITSuME Akeno Ic upper limit
  69. Observations of possible TAROT GRB transient near IC 4779
  70. Candidate Orphan GRB Optical Transient in IC 4779
  71. Las Campanas observations of possible TAROT GRB transient near IC
  72. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  73. GRB 070616: No Evidence for I Band Afterglow
  74. SN 2007bg - off-axis GRB?
  75. GRB070616: Optical Observation by MITSuME Akeno
  76. GRB 070612B: Optical Observation by MITSuME Akeno
  77. GRB070616: Optical Observation by MITSuME Okayama
  78. GRB 070616: TLS observation
  79. GRB 070612B: optical observations
  80. GRB070612A: MITSuME Okayama Observation
  81. GRB 070610: MITSuME OAO optical upper limit
  82. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  83. GRB 070520A: MITSuME Akeno optical upper limits
  84. GRB 070419A: MITSuME Okayama Observations
  85. GRB 070311: MITSuME Okayama Optical Observation
  86. GRB 070306: ART-3 early optical and near infrared constraints
  87. GRB 070220: MITSuME Okayama Optical Observation
  88. GRB 070220: ART-3 Optical and NIR limits
  89. GRB 070208: MARGE Optical Observations
  90. GRB070129: MITSuME optical observation
  91. GRB 070125: MITSuME Okayama optical observation
  92. GRB 061222A: MITSuME Akeno optical upper limits
  93. GRB 061222B: MITSuME Akeno optical upper limits
  94. GRB 061126: optical observation
  95. GRB 061121: ART detection in Ic
  96. GRB 061109: optical observation
  97. GRB 060927: Early color
  98. GRB 060906: optical observation
  99. GRB 060807: optical limit
  100. GRB060418, BVRcIc field calibration

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