HI Observations of MaNGA Galaxies
with the Green Bank Telescope

Presented by Nattida Samanso
National Astronomical Research Institute of Thailand

Introduction
Neutral hydrogen (HI)Emits an observable radiation at 21 cm
and is not absorbed throughout its path

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Image credit: Benjamin Winkel for the HI4PI collaboration (Argelander-Institut für Astronomie/Max-Planck-Institut für Radioastronomie)Radio telescope

Green Bank Telescope (GBT): The largest fully steerable single dish in the world, 100 x 110 m(c) National Radio Astronomy Observatory / Associated Universities, Inc. / National Science Foundation

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Targets selection
Mapping Nearby Galaxies atApache Point Observatory• SDSS Data Release 13• Stellar mass greaterthan 109 solar mass
• No pre-selection ongalaxy type
• Average redshift of thesample is z ≃ 0.03.
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Methods

HI detection
justification

GBT observations
Perform quick
inspection
Remove GPS signal

Data combination

Perform a fullreduction

Removing RFI andsmoothing data

Measuring galaxy’s
HI mass

Baseline subtraction
and Normalization
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Measuring galaxy’s HI mass

(Masters et al, 2014)• HI detected galaxy(Roberts, 1962)• HI non-detected galaxy
assuming rms in mJy
assuming a range of widths is equal 200 km/s

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Observational results
8568-12702
Flux (mJy)

HI detection

Flux (mJy)

Velocity of HI (Km/s)
8568-12702

Nondetection

Velocity of HI (Km/s)
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Galaxy classification with HI Detection %
100%
3%

80%

14%

60%
62%

40%
0%

EllSpira

Detected HI

Non-Detected HIUncertainLe
nt icular

Lenticularl

Uncertain

ica

EllipticalslSpirals

20%

ipt

21%

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Unexpected detection of HI gas in elliptical – supposedly“red and dead galaxies why?”
HI detection

Flux (mJy)7957-6103

Velocity of HI (Km/s)
8611-3704
Flux (mJy)

HI detection

Velocity of HI (Km/s)

9Methods
HI detection justification

Absolute magnitude
g-band, r-band

Photometric data (DRPall)
Plot g vs. g-r

Color-magnitude diagram with HI detection

Mark the detection andthe non-detection galaxy

10ecneuqes
Red

ColorRedder

Bluer

Luminosity
Fainter

Brighter
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Absolute magnitude
g-band, r-band

Methods
HI detection
justification

Photometricdata (DRPall)

Separate a region

Plot g vs. g-r

Calculate adetection fraction

Mark the detection andthe non-detection galaxy

Color-magnitude diagramwith HI detection

Color-magnitude diagramwith HI detection fraction# of HI deteced galaxies
Detection fraction =# of total observed galaxies

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Methods

Absolute magnitude
g-band, r-band

HI detection
justification

Photometric
data

Separate a region

HI mass
Plot g vs. g-r

Calculate a HI gas
fraction
Color-magnitude diagramwith HI gas fraction

Average HI mass
HI gas fraction =Average (MHI + stellar mass)
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Active galaxy
Active galactic
nucleus (AGN)
Driving gas out
and affect stars
formation in galaxy
Image credit: NASA and The Hubble Heritage Team (STScI/AURA)

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Methods
HI detection
justification

OIII, H_beta, NII, H_alpha

Optical line
flux data

Plot log [OIII/H_beta]
vs. log [NII/H_alpha]

Draw a Ke01 extreme
starburst line and Ka03
star-forming line
Baldwin-Phillips-Terlevich(BPT) diagram

17Extreme starb

AGN
urst line18

Galaxy classification with AGN Indication
300250
200
150
100
500
Spirals

Ellipticals
AGN

Uncertain

Lenticular

NormalGalaxy classification with AGN Indication %100%80%
60%
40%
20%
0%
Spirals

Ellipticals
AGN

Uncertain

Lenticular

Normal19

ColorRed sequence

Luminosity

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Conclusions
Spiral galaxy

normally HI detected galaxy

Elliptical galaxy

normally HI non-detectedgalaxy

The incidence of AGN

HI gas properties.

Most of AGN found in the red sequence21

Acknowledgements

Project advisor
Wiphu Rujopakarn, Ph.D.

Collaborators
Karen Masters, Ph.D. and David V. Stark, Ph.D.
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