Initial deep LOFAR observations of epoch of reionization windows I. The north celestial pole

[Person 40d4f138-afb2-40da-8b6d-ade166dd793d not found]; [Person c224d98e-a389-4623-8d3e-bbeb8fde641f not found]; [Person bb834949-c511-4fce-853b-7563ee22a6b8 not found]; [Person ac4b5fd5-1b56-49c2-a9d2-9c5055b52625 not found]; [Person f353bf2a-7bb6-40f8-8ea1-0176cdf41c8f not found]; [Person 948ccf3e-5ce4-452b-9da2-aad518647e97 not found]; [Person 82208fb1-d82b-48db-a641-9fcf9100d117 not found]; [Person 1615e774-2129-4b09-87c2-e68b6e0c4c30 not found]; [Person 7419c058-88ff-417b-8ad8-0798dd7c0162 not found]; [Person 009018eb-9a2f-46fb-8919-8965cf1b43cd not found]; [Person 134b68ad-e02b-4882-83eb-d814e08faf5a not found]; [Person 7943c594-cc6d-437f-b97e-477036e51432 not found]; [Person c48fe815-3cc5-4b33-8111-dc1c2d8019ce not found]; [Person 78cf6998-c24e-4616-a551-4827d8dab7e9 not found]; [Person eb61c855-8f13-449f-9f5a-5340314676bd not found]; [Person 06249a9f-67f3-427b-8174-2083a08145bc not found]; [Person f04d8e76-1daf-4a39-beef-7e4e314b6d88 not found]; [Person a4876fc7-4fe5-45b1-98f3-bbf538a15e4f not found]; [Person 6ddd4291-37a6-427f-afee-485c35eaebe8 not found]; [Person 3bc35bbc-96ed-4783-a9c6-306bd720bdfe not found]; [Person c6342976-5a73-423f-9b95-57a8c909673d not found]; [Person fbc6bcbc-1c14-4064-88d2-fe3d33185a73 not found]; [Person 4ebb0db6-8a7b-4889-a862-66cb11c1403f not found]; [Person 08fd0c5f-648e-40ff-a8bf-d580200b5a1c not found]; [Person b3252951-11b6-4872-bb35-dc6acf654575 not found]; [Person b8a8806b-8754-4a60-b5e5-b1a2375ada8b not found]; [Person 8a61903c-8991-4cc0-8a0c-a087cda4da62 not found]; [Person fc8283be-8e9c-4f96-bed4-f5b880228d58 not found]; [Person d6010bc8-bfec-47ac-b7a8-6c6fe0fcd104 not found]; [Person c1c27a2c-79d4-4888-8076-f2fba8c6c52d not found]; [Person f455e1c5-682b-4e43-afcc-24295774cfa0 not found]; [Person 912f7557-ebf5-4836-984c-f4451e4ac84a not found]; [Person 68935f12-54e8-4412-9424-3a623e22dc1a not found]; [Person 5db4a755-583e-4d67-b5c3-e90e015af13a not found]; [Person 87ac9c66-724e-4d1f-811d-3f0413c45b84 not found]; [Person 1b1cd6f2-f8f3-4731-8bda-0f8c269765bc not found]; [Person 1fb3b94c-6f3f-421c-9ec8-ac61193375a9 not found]; [Person 50ed3a96-7dbd-4715-b07d-788c2adff28c not found]; [Person 005c7bef-c4ea-4c5f-a367-337a416eb888 not found]; [Person ac2fd726-28bc-44a5-9f8a-318c7979f9ab not found]; [Person aa99979b-05dc-4ae5-90d5-951679b5bcf4 not found]; [Person 20b7d153-9274-4041-ae4a-c67b57beac6f not found]; [Person cbd56199-031c-465e-b9eb-eee238784543 not found]; [Person dc6d0b39-3372-4630-81d4-5a0ff18b0fb3 not found]; [Person 2ad1242b-3eb0-4a3a-9143-fc8807072906 not found]; [Person 93e23bb7-c6ba-49e5-8fef-2719edf983d6 not found]; [Person fef77740-6718-470a-b78f-7c1f2bdf07ee not found]; [Person a73d4c6d-c97a-48bb-a9dd-85ef0bdbc700 not found]; [Person 35dadf58-479e-45f8-b86d-ed88e07f771f not found]; [Person e08b7284-558d-4e87-809b-154f86c42c3a not found]; [Person 972a9e0c-3a55-47af-9531-bf89c2d76fac not found]; [Person acb182f9-8412-47cd-8e16-e7968ac4144c not found]; [Person 0948946a-f68d-4222-99aa-84c94fa30024 not found]; [Person 5b99914f-1942-4b5d-bd8a-59ec8fa7b6f2 not found]; [Person 7a037b69-697e-4d52-8dbc-993f9c2f5b33 not found]; [Person 14bce3e9-481c-4f4d-84e7-8ce098eac40e not found]; [Person 7d9916da-9f49-48b5-92c0-d91ff5b1c801 not found]; [Person 801a1b3e-8324-416b-a020-e0b48815feea not found]; [Person 1288c57c-2267-4cc0-81c0-f0d2ba569fa3 not found]; [Person 19a0e1d2-9b8f-4930-8ef6-2f79fa57f77c not found]; [Person 136263a6-e2ce-43eb-a517-c7dd1435f885 not found]; [Person d444efdb-c073-4615-bb23-ca81a8d3f0ac not found]; [Person e8631bbd-58f4-429f-b5b3-74992cb2d73b not found]; [Person 91b0c6b3-01bc-4677-b48b-dce65f8231a0 not found]; [Person 33b85fd7-50ef-417e-a5e7-f9bc1662cd31 not found]; [Person af79ba09-769b-4ad6-94bd-f8fd2e07481e not found]; [Person 5017dbac-dddc-422d-8ee1-7531a54372f9 not found]; [Person 05b26693-be98-468a-a4b6-3ba68fe6461d not found]; [Person 67c1e14b-20aa-4647-a996-3a211c0df304 not found]; [Person f234768a-abd1-4d40-b79f-254d3d00c512 not found]; [Person 8bb193a4-4049-4c1c-8876-b429bae0d427 not found]; [Person dc7e1703-466d-4578-ac6f-eb81059d6f00 not found]; [Person 64c4dd88-aca3-48e5-9f4a-2ab732ab05a4 not found]; [Person 477ede40-a885-43a7-8ab6-9075066e4796 not found]; [Person acc3303f-39bc-40aa-863a-894ecaedbea5 not found]; [Person 34d09656-895d-4640-afcd-8e2d81857659 not found]; [Person eace3a97-1404-4a6d-b6ae-6932bcadd8f2 not found]; [Person eadd9f19-ac7d-4e5b-8c22-4db4166ad2cd not found]; [Person 61d390e2-8e4e-4969-91cb-cd59258a5f78 not found]; [Person b1393d66-8678-4bb2-b7ef-78a21d1c42cb not found]; [Person b1612612-d636-48af-af4f-78511bf68b38 not found]; [Person 7e70a016-8fa9-494e-a8cc-7b377d62dc28 not found]; [Person 6f653f92-047f-4903-8073-451041970825 not found]; [Person 0f8f53aa-3906-4db9-bf86-56ed54e275c2 not found]; [Person ff52b872-61f0-448c-9bbe-834d51880e3b not found]; [Person d14ead25-a147-4042-b053-d18d9a0a2cf3 not found]; [Person 3920bfc1-0e43-494d-b019-b7f6addb1b64 not found]; [Person 110aef81-1eba-46bd-a334-584dab1cc979 not found]; [Person aaeac1bb-53ae-4639-a723-824ed67aeab4 not found]

doi:10.1051/0004-6361/201220874

Initial deep LOFAR observations of epoch of reionization windows I. The north celestial pole
Artikel i vetenskaplig tidskrift, 2013

Aims. The aim of the LOFAR epoch of reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21 cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to achieve this, very long integrations, accurate calibration for stations and ionosphere and reliable foreground removal are essential. Methods. One of the prospective observing windows for the LOFAR EoR project will be centered at the north celestial pole (NCP). We present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz. The data were obtained in April 2011 during the commissioning phase of LOFAR. We used baselines up to about 30 km. The data was processed using a dedicated processing pipeline which is an enhanced version of the standard LOFAR processing pipeline. Results. With about 3 nights, of 6 h each, effective integration we have achieved a noise level of about 100 mu Jy/PSF in the NCP window. Close to the NCP, the noise level increases to about 180 mu Jy/PSF, mainly due to additional contamination from unsubtracted nearby sources. We estimate that in our best night, we have reached a noise level only a factor of 1.4 above the thermal limit set by the noise from our Galaxy and the receivers. Our continuum images are several times deeper than have been achieved previously using the WSRT and GMRT arrays. We derive an analytical explanation for the excess noise that we believe to be mainly due to sources at large angular separation from the NCP. We present some details of the data processing challenges and how we solved them. Conclusions. Although many LOFAR stations were, at the time of the observations, in a still poorly calibrated state we have seen no artefacts in our images which would prevent us from producing deeper images in much longer integrations on the NCP window which are about to commence. The limitations present in our current results are mainly due to sidelobe noise from the large number of distant sources, as well as errors related to station beam variations and rapid ionospheric phase fluctuations acting on bright sources. We are confident that we can improve our results with refined processing.

Dark ages, reionization, first stars

Techniques: interferometric

Instrumentation: interferometers

Methods: data analysis

Författare

[Person 40d4f138-afb2-40da-8b6d-ade166dd793d not found]

[Person c224d98e-a389-4623-8d3e-bbeb8fde641f not found]

[Person bb834949-c511-4fce-853b-7563ee22a6b8 not found]

[Person ac4b5fd5-1b56-49c2-a9d2-9c5055b52625 not found]

[Person f353bf2a-7bb6-40f8-8ea1-0176cdf41c8f not found]

[Person 948ccf3e-5ce4-452b-9da2-aad518647e97 not found]

[Person 82208fb1-d82b-48db-a641-9fcf9100d117 not found]

[Person 1615e774-2129-4b09-87c2-e68b6e0c4c30 not found]

[Person 7419c058-88ff-417b-8ad8-0798dd7c0162 not found]

[Person 009018eb-9a2f-46fb-8919-8965cf1b43cd not found]

[Person 134b68ad-e02b-4882-83eb-d814e08faf5a not found]

[Person 7943c594-cc6d-437f-b97e-477036e51432 not found]

[Person c48fe815-3cc5-4b33-8111-dc1c2d8019ce not found]

[Person 78cf6998-c24e-4616-a551-4827d8dab7e9 not found]

[Person eb61c855-8f13-449f-9f5a-5340314676bd not found]

[Person 06249a9f-67f3-427b-8174-2083a08145bc not found]

[Person f04d8e76-1daf-4a39-beef-7e4e314b6d88 not found]

[Person a4876fc7-4fe5-45b1-98f3-bbf538a15e4f not found]

[Person 6ddd4291-37a6-427f-afee-485c35eaebe8 not found]

[Person 3bc35bbc-96ed-4783-a9c6-306bd720bdfe not found]

[Person c6342976-5a73-423f-9b95-57a8c909673d not found]

[Person fbc6bcbc-1c14-4064-88d2-fe3d33185a73 not found]

[Person 4ebb0db6-8a7b-4889-a862-66cb11c1403f not found]

[Person 08fd0c5f-648e-40ff-a8bf-d580200b5a1c not found]

[Person b3252951-11b6-4872-bb35-dc6acf654575 not found]

[Person b8a8806b-8754-4a60-b5e5-b1a2375ada8b not found]

[Person 8a61903c-8991-4cc0-8a0c-a087cda4da62 not found]

[Person fc8283be-8e9c-4f96-bed4-f5b880228d58 not found]

[Person d6010bc8-bfec-47ac-b7a8-6c6fe0fcd104 not found]

[Person c1c27a2c-79d4-4888-8076-f2fba8c6c52d not found]

[Person f455e1c5-682b-4e43-afcc-24295774cfa0 not found]

[Person 912f7557-ebf5-4836-984c-f4451e4ac84a not found]

[Person 68935f12-54e8-4412-9424-3a623e22dc1a not found]

[Person 5db4a755-583e-4d67-b5c3-e90e015af13a not found]

[Person 87ac9c66-724e-4d1f-811d-3f0413c45b84 not found]

[Person 1b1cd6f2-f8f3-4731-8bda-0f8c269765bc not found]

[Person 1fb3b94c-6f3f-421c-9ec8-ac61193375a9 not found]

[Person 50ed3a96-7dbd-4715-b07d-788c2adff28c not found]

[Person 005c7bef-c4ea-4c5f-a367-337a416eb888 not found]

[Person ac2fd726-28bc-44a5-9f8a-318c7979f9ab not found]

[Person aa99979b-05dc-4ae5-90d5-951679b5bcf4 not found]

[Person 20b7d153-9274-4041-ae4a-c67b57beac6f not found]

[Person cbd56199-031c-465e-b9eb-eee238784543 not found]

[Person dc6d0b39-3372-4630-81d4-5a0ff18b0fb3 not found]

[Person 2ad1242b-3eb0-4a3a-9143-fc8807072906 not found]

[Person 93e23bb7-c6ba-49e5-8fef-2719edf983d6 not found]

[Person fef77740-6718-470a-b78f-7c1f2bdf07ee not found]

[Person a73d4c6d-c97a-48bb-a9dd-85ef0bdbc700 not found]

[Person 35dadf58-479e-45f8-b86d-ed88e07f771f not found]

[Person e08b7284-558d-4e87-809b-154f86c42c3a not found]

[Person 972a9e0c-3a55-47af-9531-bf89c2d76fac not found]

[Person acb182f9-8412-47cd-8e16-e7968ac4144c not found]

[Person 0948946a-f68d-4222-99aa-84c94fa30024 not found]

[Person 5b99914f-1942-4b5d-bd8a-59ec8fa7b6f2 not found]

[Person 7a037b69-697e-4d52-8dbc-993f9c2f5b33 not found]

[Person 14bce3e9-481c-4f4d-84e7-8ce098eac40e not found]

[Person 7d9916da-9f49-48b5-92c0-d91ff5b1c801 not found]

[Person 801a1b3e-8324-416b-a020-e0b48815feea not found]

[Person 1288c57c-2267-4cc0-81c0-f0d2ba569fa3 not found]

[Person 19a0e1d2-9b8f-4930-8ef6-2f79fa57f77c not found]

[Person 136263a6-e2ce-43eb-a517-c7dd1435f885 not found]

[Person d444efdb-c073-4615-bb23-ca81a8d3f0ac not found]

[Person e8631bbd-58f4-429f-b5b3-74992cb2d73b not found]

[Person 91b0c6b3-01bc-4677-b48b-dce65f8231a0 not found]

[Person 33b85fd7-50ef-417e-a5e7-f9bc1662cd31 not found]

[Person af79ba09-769b-4ad6-94bd-f8fd2e07481e not found]

[Person 5017dbac-dddc-422d-8ee1-7531a54372f9 not found]

[Person 05b26693-be98-468a-a4b6-3ba68fe6461d not found]

[Person 67c1e14b-20aa-4647-a996-3a211c0df304 not found]

[Person f234768a-abd1-4d40-b79f-254d3d00c512 not found]

[Person 8bb193a4-4049-4c1c-8876-b429bae0d427 not found]

[Person dc7e1703-466d-4578-ac6f-eb81059d6f00 not found]

[Person 64c4dd88-aca3-48e5-9f4a-2ab732ab05a4 not found]

[Person 477ede40-a885-43a7-8ab6-9075066e4796 not found]

[Person acc3303f-39bc-40aa-863a-894ecaedbea5 not found]

[Person 34d09656-895d-4640-afcd-8e2d81857659 not found]

[Person eace3a97-1404-4a6d-b6ae-6932bcadd8f2 not found]

[Person eadd9f19-ac7d-4e5b-8c22-4db4166ad2cd not found]

[Person 61d390e2-8e4e-4969-91cb-cd59258a5f78 not found]

[Person b1393d66-8678-4bb2-b7ef-78a21d1c42cb not found]

[Person b1612612-d636-48af-af4f-78511bf68b38 not found]

[Person 7e70a016-8fa9-494e-a8cc-7b377d62dc28 not found]

[Person 6f653f92-047f-4903-8073-451041970825 not found]

[Person 0f8f53aa-3906-4db9-bf86-56ed54e275c2 not found]

[Person ff52b872-61f0-448c-9bbe-834d51880e3b not found]

[Person d14ead25-a147-4042-b053-d18d9a0a2cf3 not found]

[Person 3920bfc1-0e43-494d-b019-b7f6addb1b64 not found]

[Person 110aef81-1eba-46bd-a334-584dab1cc979 not found]

[Person aaeac1bb-53ae-4639-a723-824ed67aeab4 not found]

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 550 A136

Ämneskategorier (SSIF 2011)

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/201220874

Publikationsdata kopplat till DOI

Mer information

Senast uppdaterat

2025-07-03

Initial deep LOFAR observations of epoch of reionization windows I. The north celestial pole Artikel i vetenskaplig tidskrift, 2013