Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/vscience/schedule/2014Spring/BradfordtagA2850.pdf Дата изменения: Fri Sep 6 19:44:17 2013 Дата индексирования: Sat Mar 1 02:06:25 2014 Кодировка: Поисковые слова: rho ophiuchi

Proposal Identification No.:

A2850 Arecibo Observatory

Date Received: 2013-Sep-03 14:17:24 William E. Gordon Telescope Observing Time Request COVER SHEET

Section I - General Information
Submitted for Sep 1 2013. This proposal has not been submitted before. Proposal Type: General Category: Observation Category: Time Requested this semester: Hours Next Semester: Hours already used for this pro ject: Additional Hours required to complete pro ject: Minimum Useful Time: Expected Data Storage: Prop osal Title: ABSTRACT: Regular Astronomy Extragalactic 22 10

3 hours less than 100 GB

The Baryonic Content of Extremely Low Mass Galaxies

We propose continued HI observations of low mass galaxies to better quantify the galaxy mass function. At low masses, the mass function is related to the small-scale matter power spectrum. We focus here on isolated low mass galaxies, which are less affected by environmental processes as compared to similar galaxies in the Local Volume. In 2014A, we observed 61 isolated low mass galaxies with Arecibo with masses between 40-60 km/s, tripling the number of observations in this mass regime. We have determined that even isolated galaxies display significant scatter in their gas mass to stellar mass ratio and the Tully-Fisher relation as compared to more massive galaxies. The proposed observations will better constrain the scatter in the observed scaling relations and allow a more robust estimate of the baryonic and the dynamical masses. We request 32 hours of L-band observing to expand our isolated galaxy sample to lower masses. Outreach Abstract: The current accepted cosmological model makes detailed predictions for the relative number of large and small galaxies. The number of small galaxies surrounding the Milky Way is far lower than predicted by this model. However, the Milky Way itself may be responsible for reducing the number of satellites around it. By contrast, we have identified a large sample of isolated small galaxies. Isolated small galaxies are less affected by their surrounding environment and require fewer assumptions when comparing to theoretical models. We will determine the total masses of these isolated small galaxies using neutral hydrogen observations with Arecibo in order to test our current cosmological model.

Name Jeremy D Bradford Marla C Geha

Institution Yale University Yale University

E-mail jeremy.bradford@yale.edu marla.geha@yale.edu

Phone 860-817-2183 203-432-5796

Student G no

1


Additional Authors
Michael Blanton, New York University, blanton@nyu.edu, not a student.

This work is part of a PhD thesis.

Remote Observing Request

Observer will travel to AO X Remote Observing In Absentia (instructions to operator)

Section I I - Time Request
The following times are in LST. For these observations night-time is required.

Begin ­ End Interval­Interval 7:00 ­ 18:00 ­ ­ ­

Days Needed at This Interval 2

Time Constraints (Must Be Justified in the Prop osal Text) Observing must be at night to avoid standing waves (see proposal). We prefer the targets between 7:00 and 18:00 LST to be scheduled for two consecutive days.

Next Semester Time Request

Begin ­ End Interval­Interval 21:30 ­ 3:00 ­ ­ ­ 2

Days Needed at This Interval 1


Time Constraints (Must Be Justified in the Prop osal Text) Observing must be at night to avoid standing waves (see proposal). The third day with targets between 21:30 and 3:00 LST may be split up into chunks of 3 hours over a flexible range of dates when these targets are up at night.

Section I I I - Instruments Needed
L-wide Atmospheric Observation Instruments:

Sp ecial Equipment or setup:

none

Section IV - RFI Considerations Frequency Ranges Planned
1425 - 1445

Section V - Observing List Target List
See proposal for target list.

3