SN 2011by

{{ Supernova |

| name = SN 2011by

| image= File:Supernova SN 2011by in NGC 3972.jpg

| caption = Image from Richie Jarvis [http://nebul.ae/astro-imaging/galaxies/ngc3972/2011-05-03-ngc3972-supernova-sn2011by1-301]

| epoch = J2000

| SNRtype =

| type = Type Ia

| ra = {{RA|11|55|45.56}}

| dec = {{DEC|+55|19|33.8}}

| host = NGC 3972

| constellation = Ursa Major

| gal =

| discovery = April 26, 2011 (UTC)

| iauc =

| mag_v = < 12

| progenitor =

| progenitor_type =

| b-v =

| notes =

}}

SN 2011by was a supernova in NGC 3972. It was a type Ia supernova, discovered by Zhangwei Jin and Xing Gao (China). SN 2011by is about 5.3" east and 19.1" north of the center of NGC 3972.Rochester Astronomy {{cite web | url = http://www.rochesterastronomy.org/sn2011/sn2011by.html | title = Rochester Astronomy: Supernova 2011by in NGC3972 }}{{cite web | url = http://www.aavso.org/aavso-alert-notice-438 | title = AAVSO: SUPERNOVA 2011by in NGC 3972 = PSN J11554556+5519338 }}