Mapping the HI Neighborhood Around Starburst Dwarf Galaxies Megan Johnson NRAO, Green Bank Tully-Fisher Workshop, April 2012

Outline Introduction NGC 1569 –Review of stellar and gas kinematics from LITTLE THINGS –GBT map NGC 4163/NGC 4214 Future Work Summary April 2, 20122Megan Johnson - TF 35

Introduction Starburst = short-lived intense period of star formation that is unsustainable over the Hubble time due to the limited supply of gas within a galaxy (McQuinn ); generally, interactions/mergers are triggers Dwarf Galaxy = low luminosity, low mass system, contained in a dark matter halo; believed to be the “Building Blocks” of larger galaxies Starburst Dwarf Galaxy = possibly a “Building Block” in action? What is the role of interactions/mergers between dwarf galaxies? April 2, 20123Megan Johnson - TF 35

April 2, 20124Megan Johnson - TF 35 Introduction Can HI environment around starburst dwarf galaxies provide clues to their interaction/merger history?

5 A B NGC 1569 – What is its shape? Member of IC 342 Galaxy Group D = 3.36 Mpc (Grocholski ) M V = SFR = 0.24 M  /yr HI mass = 2.5 x 10 8 M  Stellar mass = 2.8 x 10 8 M  Megan Johnson - TF 35April 2, 2012 Stellar and Gas Kinematics  V max /σ z

April 2, 2012Megan Johnson - TF 356 “HI Companion,” “HI Bridge,” Stil & Israel (1998) and “NCM HI Cloud” – Stil & Israel (2002) - HV3 “Chimney” - Hunter et al. (1993); Mühle et al. (2005); Westmoquette et al. (2008) Previous Work:

Stellar Kinematics April 2, 2012Megan Johnson - TF 357

April 2, 2012Megan Johnson - TF 358 Position-Velocity Diagrams – Stars and Gas

Ionized Gas in NGC 1569 B A April 2, 20129Megan Johnson - TF 35

Stellar Velocity Dispersions April 2, 2012Megan Johnson - TF 3510 = 21 ± 4 km/s SSC B SSC A Constant

April 2, 2012Megan Johnson - TF 3511 Bulk Motion Extraction

V max = 50 ± 10 km/s Bulk Motion Extraction April 2, 2012Megan Johnson - TF 3512 Bulk VF Strong NCM Weak NCM Strong + Weak

April 2, Megan Johnson - TF 35 Rotation Curve of NGC 1569 V max = 50 ± 10 km/s

April 2, Megan Johnson - TF 35 Baryonic TF Relation – Trachternach ★ NGC 1569 Total Baryonic Mass = 6.8 x 10 8 M 

April 2, 2012Megan Johnson - TF 3515 GBT Map around NGC km/s UGCA 92 NGC 1569 Southern HI Extension

GBT Map around NGC km/s Intergalactic Filaments MW Cloud UGCA 92 NGC 1569 April 2, 2012Megan Johnson - TF 3516

NGC 4163 Member of Canes Venatici Cloud D = 2.8 Mpc M V = SFR = 9.1 x M  /yr HI mass = 1.4 x 10 7 M  Stellar mass = 2.7 x 10 7 M  April 2, Megan Johnson - TF 35

NGC 4163 – IWM Velocity Field April 2, Megan Johnson - TF 35

NGC 4214 D = 2.9 Mpc M V = SFR = 0.13 M  /yr HI mass = 5.8 x 10 8 M  Stellar mass = 4.8 x 10 8 M  Member of Canes Venatici Cloud April 2, Megan Johnson - TF 35

NGC 4214 – IWM Velocity Field April 2, Megan Johnson - TF 35

UGCA 7605 UGCA 7559 UGCA 7599 NGC 4244 NGC 4214 NGC 4163 NGC 4190 Integrated HI GBT Map April 2, Megan Johnson - TF 35 RMS = 25 mK, (at 1σ in a 1 km/s channel)

April 2, Megan Johnson - TF 35 What about field dwarfs? Are nearby dwarf irregular galaxies still assembling? GBT proposal to map all LITTLE THINGS dwarfs

April 2, Megan Johnson - TF 35 IC 1613 – Local Group Member

April 2, Megan Johnson - TF 35 DDO 165 – M81 Group Member

April 2, Megan Johnson - TF 35 DDO 46 – No Known Group

Summary NGC 1569 is a thick disk –V max / σ z = 2.4 ± 0.7 –Stars and gas kinematically follow each other –Extended HI emission to south and northeast of NGC 1569 in VLA map stretching in the direction of UGCA 92 and confirmed with GBT NGC 4163/4214 –“Unsettled” HI in VLA maps –Possible extended emission detected in GBT map … stay tuned … LITTLE THINGS - ?? April 2, Megan Johnson - TF 35

April 2, Megan Johnson - TF 35

Ultra-dense HI Cloud (UDHIC) Hα tail – Velocity ~ -90 km/s (Tomita et al. 1994)

Integrated HI Intensity Contour Map April 2, 2012Megan Johnson - TF 3529